Defence of the Reich
The Defence of the Reich is the name given to the strategic defensive aerial campaign fought by the Luftwaffe over German-occupied Europe and Germany itself during World War II. Its aim was to prevent the destruction of German military and civil industries by the Western Allies. The day and night air battles over Germany during war involved thousands of aircraft, units and aerial engagements to counter the Allied strategic bombing campaign. The campaign was one of the longest sustained in the history of aerial warfare. Along with the Battle of the Atlantic and the Allied blockade of Germany, it was the longest campaign during 1939–1945. The Luftwaffe's fighter force (Jagdwaffe), defended the airspace of German-occupied territory against attack, first by RAF Bomber Command, and then Bomber Command and the United States Army Air Forces (USAAF).
In the early years, the Luftwaffe was able to inflict a string of defeats on Allied strategic air forces. In 1939, RAF Bomber Command was forced to operate at night as casualties to unescorted heavy bombers became too heavy. In 1943, the USAAF suffered several reverses in daylight and called off the offensive over Germany in October that year. The British built up their bomber force and introduced navigational aids and tactics such as the bomber stream that enabled them to mount larger and larger attacks with an acceptable loss rate.
In February 1944, the USAAF introduced the P-51 Mustang, a fighter capable of escorting the USAAF bombers to and from their targets. By the spring of 1944, the aerial defenders of the Third Reich, the Reichsluftverteidigung (RLV), were stretched to the limit and the Luftwaffe lost air superiority. By the summer 1944, the Luftwaffe was suffering from chronic fuel shortages and a lack of trained pilots. It ceased to be an effective fighting force by 1945.
The intensification of night bombing by the RAF and daylight attacks by the USAAF added to the destruction of German industries and cities which caused the economy to collapse in the winter of 1944. By this time, the Allied armies had reached the German border and the strategic campaign became fused with the tactical battles over the front. The air campaign continued until April 1945 when the last strategic bombing missions were flown. It ended indefinitely upon the capitulation of Germany in May 1945.
German defensive strategy 
The Luftwaffe lacked an effective air defence system early in the war. The daylight actions over German controlled territory were sparse in 1939–1940. The responsibility of the defence of German air space fell to the Luftgaukommandos (air district commands). The defence systems relied mostly on the Anti-aircraft artillery (AAA) arm. The defences were not coordinated and communication was poor. This lack of understanding between the AAA and flying branches of the defence would plague the Luftwaffe throughout the war. Adolf Hitler in particular wanted the defence to rest on AAA as it gave the civilian population a "psychological crutch" no matter how ineffective the weapons. Germany's Ruhr region, frequently targeted by Allied raids during this time, proved particularly difficult to defend as resources became increasingly strained. Frequently, the only air units available for Ruhr defence were the Luftgaukommandos, which were assigned specific objectives and lacked an effective ground-to-air control system to aid in interception of enemy aircraft.
On 21 September 1939, Hans Jeschonnek the Luftwaffe's Chief of Staff, clarified the role of the day fighter force in the defence of German territory. Fighter units earmarked for specific defensive tasks would remain under local air-defence command. However, all other fighter units would be organized under one of several Luftflotten (Air Fleets), which would prosecute the defence of German targets in a manner "linked directly with the strategic concept for the continued conduct of the air war". In other words the Luftwaffe fighter force would act as both a defensive and offensive force, maintaining air superiority over enemy air space would prevent enemy attacks on German-held territory.
This kind of strategy worked well at the front, but it soon became clear that a lack of training, experience and coordination between the Fliegerdivisions (Flying Divisions) and the AAA arm, when dealing with strategic defensive operations, made an effective defence difficult. With the AAA defences ineffective and seven Gruppen covering German air space, the vital industries were not well protected. This system remained in place for so long because the Allied air forces were too weak to take advantage of the situation.
Most of the battles fought by the Luftwaffe on the Western Front would be against the RAF's Circus raids and the occasional daylight raid into German air space. This was a fortunate position since the Luftwaffe's strategy of focusing its striking power on one front started to unravel with the failure of Operation Barbarossa, the invasion of the Soviet Union. The "peripheral" strategy of the Luftwaffe, advocated by Jeschonnek, had been to deploy its fighter defences at the edges of Axis occupied territory, with little protecting the inner depths.
German weaknesses 
Although the Luftwaffe eventually allocated more resources to the coming campaign than the RAF did during the Battle of Britain in 1940, it failed to commit these resources at a time when the Allied air offensives might have been checked. The Luftwaffe's crucial mistakes in leadership, production and training decisions that eventually cost it the campaign were made in 1940-1942. The German leadership failed to develop a coherent strategy for a long war. Strategic and operational ineffectiveness coupled with a failure to assign air defence as a top priority undermined the Luftwaffe's efforts in 1943-1945. German strategy, termed the cult of the offensive, worked in 1939-41, but when faced with an attrition war, the growing power of its enemies, its forces spread thin over four fronts, the failure to develop defensive doctrines, tactics and plans led to defeat.
Organisation and planning 
The Jagdwaffe defences of Germany were not considered a part of the offensive air effort. The German strategy of focusing on offensive aviation to achieve superiority on the enemy, thus home fronts, meant the force was considered second-rate and unimportant. It did not receive the investment it needed and was too weak in respect of other Luftwaffe arms for proper expansion after the start of hostilities. As a consequence, the force had no representation in the High Command. The organisation remained split under different Air Fleets and was not put under a unified command. When the need for some sort of air defence was recognised before the outbreak of war, the rush to build the Jagdwaffe was so fast that quality in cohesion and organisation suffered. The expansion, when it did come, came too late. Only nine Jagdgeschwader were in existence in 1939, and no new Geschwader (Wings) were created until 1942. The years 1940 and 1941 were wasted. Only eight were created for defence duties, and the force increased in size by only ⅓. The growth of the force and its concepts owed much to the activity of its enemies. The planning of defence was always reactive.
Developments and equipment 
No tactical-technical section existed in either the RLM or OKL. The Luftwaffe was therefore unable to provide appropriate equipment for the task asked of its units. Starting in 1940, all planning was short-sighted as a matter of policy. The need for technical improvements was resisted as pushing through upgrades would have reduced production rates of standard aircraft. Hardware would have to be turned over to the production of new types, causing a drop in output. This meant obsolete sub-variant or main types were kept in production too long. Adding to this failure, the OKL failed to produce adequate numbers of aircraft and refused to cut bomber production in favour of fighters until mid-1944. Even when these events were corrected, procurement was poor. The Messerschmitt Me 262 could not be introduced fast enough and too much time was wasted between operational testing, tactical-doctrinal development and training. General der Jagdflieger (General of Fighters) Adolf Galland took responsibility for this failure.
Pilot selection and training 
One of the most damaging elements of this aspect was the Luftwaffe's intent on giving preference to the bomber arm when it came to highly trained personnel. Flight schools were more interested in turning out bomber pilots than fighter pilots. The Luftwaffe failed to recruit engineers and highly educated personnel like the Kriegsmarine and Waffen SS. The organisation lacked a sufficient supply of commissioned pilots of fighter forces. This neglect meant a lack of combat leaders later in the war. Galland himself noted that pilot training for trainees was too limited in flying hours received. Too little training was received on operational types, formation flying, gunnery training, combat training, and a complete lack of instrument training were mistakes. Galland asserted that the lack of instrument training had not been corrected until late in the war.
Staff training 
Staff training was also uneven and neglected. Systematic training of formation leaders was not begun until after 1943. It created a lack of trained and experienced flight leaders in 1943-1945. This was far too late to help in the Defence of the Reich campaign. The trained and experienced leaders that did exist were replaced in 1940 by younger and less experienced leaders too quickly (owing to Göring's frustration with them during the Battle of Britain). Later, Göring did the same thing with Jagddivision (Fighter Division) commanders. The high turnover in the division made gaining experience impossible. Making matters worse, there were no fighter command organisations at the start of the war and there were never enough good officers to staff those that were set up. The Luftwaffe had very few General Staff Officers.
Damaging the German effort further, just 5% of Luftwaffe staff officers had technical degrees, and most were technicians in low esteem. Most came from classical schools (Humanistische Gymnasien) rather than technical schools (Real Gymnasien). This caused a lack of interest and understanding of critical technology, particularly radar, which was underestimated. There was also a tendency to neglect both intelligence and logistics. Examples of these failings was the appointment of Hans Jeschonnek, who was promoted to a position beyond his capabilities.
Strategic and Operational tactics 
The successive mistakes meant the Jagdwaffe was overloaded with missions after 1942. The successive draining of resources from the Defence of the Reich to the Eastern Front went on for too long which hampered an early build-up of RLV forces. It was slow and piecemeal and lacked any formal planning. The OKL damaged the fighting efficiency of fighter groups by transferring them away from their Geschwader command. Logistics, organisation and communications were neglected when moving units causing confusion and reducing operational readiness.
Bad weather operations completely overtaxed fighter units and inflicted high losses which caused a drop in morale and confidence in the High Command. The OKL itself did not understand the need for economical employment of strength with respect to the RLV. All raids had to be met at full strength, rapidly wearing down the defenders. Contributing to the wearing down of fighter units was the insistence on using the Bf 110 and Me 410, with unwieldy and large 37mm and 50mm calibre Bordkanone cannon. Both types had to be withdrawn from daylight combat due to losses.
In 1944, bomber commanders were allowed to conduct flight operations with disastrous results. They were not qualified to lead fighter formations. Heavy losses ensued which required rest and reorganisation. During the course of the conflict, the OKL never understood the importance of time, the need to rest, plan and recover to prolong defensive operations. Keeping units in the frontline wore them out.
Another contributory factor was the lack of attention paid to Adolf Galland's basic rules of combat. In the tactical battle, he argued that the fighter must fight on the offensive, even when on defensive missions. There was no place for a defensive posture. An example of this dictum being ignored was the instance of having Bf 109 groups escort vulnerable and modified Fw 190s, which reduced the power of interception formations. Combat cohesiveness was also often lost, and the integrity of the formations became compromised (owing to a lack of experienced leaders). This aspect of maintaining integrity regardless of the situation was often ignored. Fixed tactics contributed to failures as well. Rigid tactics were allowed to take root, and technique suffered. Using surprise, cunning and manoeuvrability had to be combined with aggressiveness and improvisation depending on the situation. This tactical nous was lost over time.
German production failures 
No effort was made to address the low production output of the German aviation industry to support the expected increased attrition rates as the so-called "Göring program" envisaged the defeat of the Soviet Union in 1941. Even as early as September 1939, the industry was failing to reach planned production by as much as 33%. Erhard Milch's reforms expanded production rates. In 1941, an average of 981 aircraft (including 311 fighters) were produced monthly. In 1942, this rose to 1,296 aircraft of which 434 were fighters. But increases were complicated by the demand for production by the other two services. Milch informed Göring that the aviation industry was allocated 74% of all aluminium resources, but 5,116 short tons (4,641 t) went into production for ammunition such as shell cases for artillery units. Milch considered this a mistake. He pointed out such reserves could have built 1,000 Dornier Do 217 heavy bombers and 4,000 Messerschmitt Bf 109. Milch ordered a crack down on wasteful practices. He ordered metals to be recycled, and metals from crashed aircraft to be used again. This way he increased the availability of metals by 57%. In spite of the failures of the High Command and Göring, the Luftwaffe's resourceful administrators just managed to stabilize German aircraft numbers.
Hans Jeschonnek initially opposed Milch's planned production increases. But in June, he changed his mind and suggested 900 fighters per month should be the average output. By the winter of 1941–1942, just 39% of the fighter force was operational and possessed just 60 more combat aircraft than it did in June 1941, despite its increased commitments. Throughout 1942, the Luftwaffe was out produced in fighter aircraft by 250% and in twin-engine aircraft by 196%.
The intensification of Allied bombing caused the dispersion of production and prevented an efficient acceleration of Milch's expansion program. The German aviation production reached about 36,000 aircraft for 1944. However, by the time this was achieved the Luftwaffe lacked the fuel and trained pilots to make this achievement worthwhile. The failure to maximize production immediately after the failures in the Soviet Union and North Africa ensured the Luftwaffe's effective defeat in the period of September 1943–February 1944. Despite the tactical victories won, they failed to achieve a decisive victory. By the time production reached acceptable levels, it was too little too late.
Repelling RAF Bomber Command (1939–1941) 
Daylight operations 
The RAF developed a doctrine of industrial air bombardment in the years leading to the Second World War. RAF strategists deemed the attacks on large areas of industrial cities were the best that could be achieved due to a lack of accuracy in bombing technology. This doctrine was also a result of the RAF's Air Chief Marshal, Charles Portal's conviction that attacking German morale would be a key method of forcing capitulation. Portal presented a convincing argument that "morale bombing" would complement strategic bombing as it would target German industrial workers, either undermining their morale or killing them, thus crippling German military industry. This belief stemmed from the policy of Hugh Trenchard, the first Air Chief Marshal, of carrying the offensive war to the enemy homeland, a policy which originated during the First World War. It was hoped that such physical and psychological damage would be done, in Germany and German-occupied territories, that the people would take up arms and overthrow the system.
Despite this ambitious strategy, the RAF had entered the Second World War without a bomber fleet that was fit for the purpose of large-scale strategic bombing. In common with all unescorted bombers, was vulnerable in daylight raids to fighter aircraft. From September 1939-May 1940, both sides resorted to avoiding civilian targets. In the case of Bomber Command, dropping leaflets was the main task.
The longest defensive air campaign of the Second World War began on the afternoon of 4 September 1939, just one day after Britain's declaration of war on Germany. The target for RAF Bomber Command was the German naval base at Wilhelmshaven. These raids continued into December 1939. In the aerial engagement dubbed the Battle of the Heligoland Bight on 18 December 1939, the RAF lost 12 of 22 bombers. Bomber Command had been forced to admit defeat in the opening days of the war, and switched to night bombing.
British strategists argued over the nature of British strategy in the 1939–1941 period, the essence of which would form the fundamental base of RAF strategy throughout the war. Bombing results were also wrangled over and formed the key to the issue. Some in the Air Ministry argued that the bombing technology was not accurate and as a result of this precision attacks could not be undertaken. To support their findings, they used the Butt report, which indicated only 30% of RAF bombers arrived within the target area, and just 10% within the Ruhr region. Those in RAF Bomber Command who were in favour of precision bombing of selected targets criticised the report as "selective". When Air Marshal Arthur Harris took over RAF Bomber Command in 1942, he was to use this as a tool to push for his area bombing policies.
Night operations 
Kammhuber recruited pilots Hermann Diehl and Wolfgang Falck to his command. They were important figures in developing the night fighter system. Using Freya, they could bring interceptors within 500 m (550 yd) of enemy aircraft. Diehl had helped develop radar controlled defences for daylight operations which were used at the Battle of the Heliogoland Bight in December 1939. Falck used two Würzburg sets during night operations in April 1940 and both recommended a command and control system using these technologies. Falck himself developed Hellenachtjagd (Bright Night Fighting). It involved Würzburg-controlled searchlights supported by 12 purpose-built nightfighters. This concept was limited, as searchlights could not operate in thick vapour of more than 5⁄10 cloud conditions.
Although Kammhuber was sceptical about radar, he established Kombinierte Nachtjagdgebeite (Combined Night Fighting Zones) around prime targets in which fighters cooperated with Würzburg sets supported by AAA. Although not successful at first, results soon improved. It was halted around October 1940, as a lack of long-range radar made it an unsuitable method. A second system, suggested by Diehl, involved a Freya married to a searchlight (Parasitanlage, or Parasite installation). It was designated Dunkelnachtjagd (Dark Night Fighting). It proved difficult to implement owing to production delays with the Freya. Kammhuber began to realise the potential of airborne radar at this time. After consulting Wolfgang Martini, a technical specialist in the Luftwaffe, the development of Lichtenstein radar began.
Despite the Germans having only a fledgling defence, most of Bomber Command's operations against Germany in 1940-1941 failed. In the second half of 1940 170 RAF bombers failed to return. Only 72 of these were due to growing German competence in night fighting; 42 were claimed by the Luftwaffe and 30 by AAA units. The rest simply ran out of fuel. Most of these cases were caused by poor navigation training in the pre-war era. RAF loss rates were twice those of the Luftwaffe during The Blitz in the period, July 1940 and June 1941. The defeat of the night offensives were achieved by a force with less than 60 aircraft in 16 staffeln (Squadrons). Night fighter defences claimed 421 RAF bombers in 1941.
One notable tactic was Kammhuber's offensive action. In keeping with the Luftwaffe's defence by offensive action over enemy territory, Kammhuber suggested tracking bombers and attacking them as they took off from their bases in Britain. Hitler refused in the grounds that the German people needed to see the British bombers being brought down over Germany so as to be convinced they were being defended. After October 1941, the Luftwaffe stopped their mini offensive. Hitler's decision relieved Harris and Bomber Command. In 1940–1941 these intruders had been responsible for two-thirds of the RAF losses. The chance to wreak havoc on the bomber offensive was lost. In response, Kammhuber concentrated on building the Kammhuber Line.
Organisation of defence 
The failure of the Luftwaffe to protect Berlin from a series of small scale raids made by RAF Bomber Command during the Battle of Britain led to the construction of a solid air defence programmes. Luftflotte Reich was eventually produced, which protected all of Germany and Central Europe. Reichsmarschall Hermann Göring ordered General-Leutnant (Lieutenant General) Hubert Weise, who had commanded the I.Flakkorps (1st Flak Corps) with distinction during the Battle of France, to form Luftgaukommando III on 27 September 1940. This Command was originally meant to protect Berlin but grew to encompass all air-defences as far south as Dresden. Weise formed Luftwaffenbefehlshaber Mitte (Central Air Force Command or "Air Command Central" – Lw Bfh Mitte) on 24 March 1941. Weise also created the Nachtjagddivision (Night-Fighter Division) under the command of Major-General Josef Kammhuber to combat the night operations of Bomber Command. However, the defence of southern Germany was given to Hugo Sperrle's Luftflotte 3. This caused coordination problems as the two forces were competing. Erhard Milch urged Göring to unite the fighter force under one command as had been the case for RAF Fighter Command in the Battle of Britain. Göring refused. Until Luftflotte 3 was practically destroyed in the Normandy Campaign in August 1944, the home defences remained split between rival commanders.
Growth of night defences 
The German attitude to air defence was built on the 'counterair' action. Air superiority would be attained and won over enemy airspace, safeguarding the homeland from attack. Despite this, many of the ingredients for an improvised defence were on hand or under development in 1939. The Germans possessed large numbers of AAA batteries, of good quality and varying calibers supported by searchlights, sound detectors and visual ranging apparatus. They were also deploying Freyar radar on the coastlines supported by observer networks. Shortly, the Würzburg set was to be introduced. This radar was fire-controlling, allowing AAA installations to deliver well-aimed AAA fire. The Luftwaffe supported its defences with its main dayfighter, the Messerschmitt Bf 109 while it had no night fighters. There was also no centralised control system and air units were not directed closely from the ground, as was the case with RAF Fighter Command.
When Bomber Command began attacks by night in May 1940, the Germans had no way of intercepting incoming formations of RAF bombers. Attempts began at creating a night fighter defence. These trials, which started pre-war, used a warning service based on sound detectors and searchlights. Night fighters orbited the beacons at altitude outside illuminated area, when a bomber was caught in the light, the fighter engaged the aircraft. Any focusing of searchlights at altitude signaled the night fighter to enter the illuminated zone and attack. AAA units were ordered to fire at every given opportunity, other than when the fighters were in the combat zone. These experiments ceased in August 1939. By 1940, fighters were reliant on searchlight-aided AAA.
In response to Bomber Command's offensive in 1940, Josef Kammhuber was asked to develop a night defence. Over the next three years he developed a sophisticated defence known to the British as the Kammhuber Line. Kammhuber began by expanding the illuminated zone which extended from occupied Denmark to northern France. Early warning relied on Freyar radar, sound detection devices and observers. Control of the night fighters and AAA batteries was provided by short-range Würzburg sets. The next step was the need to procure a capable night fighter design. The Germans did not have one, but improvised and used the Messerschmitt Bf 110 heavy fighter and Junkers Ju 88 medium bomber. They both proved exceptional in the role.
With an operational system now online, tactical considerations were developed. The first was airborne raid sets, installed on fighters. German pilots complained about this as it created drag and reduced the performance of their aircraft. They preferred to acquire the target visually once ground control had guided them onto the bomber stream. A second change involved the removal of AAA installations and searchlights from the line and grouping them around cities for their defence.
The system had some weaknesses. The line was composed of a series of contiguous boxes. The boundaries were defined by Würzburg radar. The awkwardness of the plotting system used within each box prior to 1942 and the absence of an air-mounted IFF (Identification Friend or Foe), meant that only one fighter at a time could be controlled from the ground. One Würzburg controlled the fighter, the other tracked the bomber. The two plots were not represented on a single radarscope; they came from to different individual operators, each of whom projected a different coloured circle on a plotting table. The controller radioed directions to the fighter on the basis of data provided by the plotting table. Until IFF became available, blips could not be identified.
When operators lost fighters, which often happened, they had to return to the beacon in that particular box. Moreover, Würzburg radar measurements from two sets, could be as much as 500 m (550 yd) out. Compounding command, control and communication problems, a failure to intercept usually resulted. Airborne radar solved this problem. Initially, the UHF-band Lichtenstein BC radar set, the first such radar unit used by the Luftwaffe, had a narrow search angle and when a bomber employed radical evasive manoeuvres, contact could be lost. Despite its weaknesses, growing sophistication and better organisation, the Kammhuber Line would become a formidable obstacle.
USAAF join the battle (1942) 
The new enemy 
The entry of the United States (U.S.) into World War II on 11 December 1941 after Hitler's declaration of war, was an unwelcome shock for the OKL. For the first year, the expected all-out offensive against German targets did not come. But by the end of 1942, the Luftwaffe was still stretched thin on the Eastern Front and its most powerful air command, Luftflotte 4 was engaged in the Battle of Stalingrad. In North Africa, the Luftwaffe was losing air superiority, the RAF was increasing its fighter sweeps over France, and its night bombing campaign of German cities was starting to increase in intensity. In May 1942, the bombing of Cologne had given the RAF its first success. Despite this the defence of German air space was given low priority as the Reich expanded on all fronts. On 16 May, in a conference, Hermann Göring made a rare perceptive observation. He noted that if enemy bomber formations started penetrating the German fighter defence at the Channel coast, there was "nothing left in Germany to oppose them". This was correct, but at that time the lack of any mass attacks by the USAAF units arriving in Europe and the failure of RAF bombing in daylight meant few senior commanders were concerned with this development.
The two USAAF Air Forces that bore the burden of the fighting in the European Theatre of Operations (ETO) were the Eighth Air Force and the Fifteenth Air Force. The American groups were equipped with B-17 Flying Fortress and the B-24 Liberator heavy bombers. The B-24 had a superior speed, range and bomb load to the B-17, but it could not maintain formation in altitudes above 21,000 ft (6,400 m) making it more vulnerable to AAA and fighter attack.
The American command did not see the need for long-range fighters in 1942, and like Bomber Command in the early war period, believed the bomber would always get through. On that understanding, there was no a rush to develop fighter aircraft of this type. The mid-range P-38 Lightning had been designed as an interceptor and was adequate in the escort role. Production had not yet reached the output needed and losses in the Mediterranean had diverted the P-38 strength there. As an interim solution the Americans were given the British Spitfire, but it lacked the range to reach beyond the coastal areas of western Europe.
American strategic aims 
American strategic policy differed from that of the RAF. German civilian morale was not a primary objective for the planners of the USAAF. American air intelligence believed attacks against economic targets, such as electric and industrial power could achieve the results sought by the RAF, without resorting to what it considered "indiscriminate civilian bombing".
According to American intelligence, by late 1941 the German Wehrmacht and its supporting industry was already stretched thin and suggested that certain targets would be particularly sensitive to attack. As a result, oil and petroleum and synthetic rubber were added to the American "Air War Plan 42". These targets became the focus of the American effort due to the mistaken belief that the Wehrmacht was mostly motorised. In 1942 and 1943, U-Boat bases were added due to the growing threat in the Battle of the Atlantic at that time. But the largest difference in American and British was the emphasis the Americans placed on destroying the Luftwaffe. In the British view, this would be achieved by paralysing the German economy.
The American agenda, sent up in June 1943 planned a strike at the German air industry, which was considered a prerequisite to any aerial and or land offensives on the continent. Its aim was to defeat the Luftwaffe in the air, on the ground and to destroy its aviation industry to a degree that it could no longer pose a threat to an Allied invasion of the continent. General Ira C. Eaker had proposed a combined offensive for this operation, named Operation Pointblank. Its plan was based upon selection, or precision attack by USAAF forces in daylight, supported by the area bombing methods of Bomber Command at night. Harris, however, was reluctant to divert forces for precision attacks. Instead, he favoured area bombing against industrial cities. Bomber Command's success during the Battle of the Ruhr and the Battle of Hamburg, and the failures of the USAAF to make an impact in 1943 also seemed vindicated Harris' policy. Heavy losses among unescorted bombers for little return would ensure a suspension of deep penetration raids in October 1943. It was not until the introduction of a new tactical weapon, the long-range P-51 Mustang fighter, that could escort bombers deep into Germany and back, that a daylight strategy became possible.
German view 
The German command had little respect for American aviation. Göring assured Hitler that the B-17 was of miserable fighting quality, and the Americans could only build proper refrigerators. Generaloberst (General-Colonel) Hans Jeschonnek stated, while listening to a lecture on Allied offensive potential in July 1942, that "Every four-engine bomber the Western Allies build makes me happy, for we will bring these down just as we brought down the [British] two engine ones".
This was a poor state of affairs considering German intelligence sources in Washington, prior to hostilities, had picked up detailed reports on the performance and potential performance of American aircraft. It did not take long for Hans Jeschonnek to change his mind. He was impressed by these reports and had sent them to Hitler and Göring to underline the threat posed by the USAAF. As far as he was concerned, mass production and development of new interceptors must be given immediate priority. Hitler ignored them and agreed with Göring. Jeschonnek despaired. He wrote to General Friedrich von Boetticher (who had been part of the German military attaché in Washington):
Boetticher, we are lost. For years I have, on the basis of your reports, forwarded demands to Göring and Hitler, but for years my requests for the expansion of the Luftwaffe have not been answered. We no longer have the air defence I requested and which is needed...we no longer have any time...to provide ourselves with the weapons to fight the dreadful threat which you have predicted and reported to us. Then we will be covered from the air with an enemy screen which will paralyze our power to resist.
Jeschonnek lacked the personality to force the reality of the situation onto his superiors. In the end, unable to assert himself, official optimism won the day.
German procurement problems 
Moreover, the front line units in the West were complaining about the poor numbers and performance of aircraft. Units complained of lack of Zerstörer (Destroyer) aircraft with all weather capabilities and the "lack of climbing power of the Bf 109". The Luftwaffe's technical edge was slipping as the only formidable new aircraft in the German arsenal was the Fw 190. Generalfeldmarschall Erhard Milch was to assist Ernst Udet with aircraft production increases and introduction of more modern types of fighters. However, they explained at a meeting of the Reich Industrial Council on 18 September 1941 that the new next generation aircraft had failed to materialise, and obsolescent types had to be continued to keep up with the growing need for replacements.
In 1941, the Fw 190 fighter began to partially replace the Bf 109 as the main Luftwaffe fighter type. The Fw 190 proved to be more manoeuvrable and better armed, but its performance above 20,000 ft (6,100 m) dropped considerably. The Bf 109 variants could fight well at high altitudes and were a match for Allied fighters in performance. So it was decided by the OKL to keep both the Fw 190 and Bf 109 in production. In later stages of the campaign the Fw 190s were equipped with heavy armament decreasing their performance at high altitude even further. They were to be used primarily as bomber destroyers while the Bf 109, the better of the two at high altitude, would engage any escorting fighters.
German daylight air superiority (1942–1943) 
German priorities 
The American build up in the ETO was slow. Over a year had passed since Adolf Hitler's declaration of war on the U.S. before the first USAAF air attack was carried out over Germany. Small formations of USAAF B-17s had operated over France and the Low Countries in 1942, but like the RAF missions of 1940–1941, achieved little. Their first raid on Germany targeted Wilhelmshaven on 27 January 1943. At this point, only one German fighter wing (Jagdgeschwader 1) .
The German air defences at this time consisted of the Luftwaffenbefehlshaber Mitte, protecting the Netherlands and Germany. Luftflotte 3 protected Belgium and France. Lw Bfh Mitte consisted of only 179 fighters. Hitler and Göring could not be persuaded to expand the fighter arm at the expense of the bomber arm, and any further reinforcements would have to come from other theatres of war.
The Luftwaffe leadership continued to press for the production of bombers; little attention was paid to new types of fighters. On 22 February 1943, at a conference with his senior staff, including Milch and Jeschonnek, Göring refused to accept the Americans had a decent fighter design. The P-47 Thunderbolt that was appearing over German air space was considered inferior to the German fighters.
On 18 March 1943, Göring contradicted his earlier assumptions and complained that the designers had failed him. He claimed that the Bf 109 was nearing the end of its useful service life and there was no replacement on the horizon. Milch and Albert Speer, the newly appointed armaments minister, could do little to develop the new aircraft as their energies were directed to increasing production of existing types in response to the growing Allied offensive. Types like the Focke-Wulf Ta 152, Dornier Do 335 and Messerschmitt Me 262 were delayed for various reasons. The air battles of 1943 and 1944 were fought by the old types, the Messerschmitt Bf 110, the Bf 109, Fw 190 and Ju 88.
Defeat of American day offensive 
The efficiency and performance of the German fighter arm reached its peak during 1943. Without an escort fighter with sufficient range, USAAF bombing raids into Germany proper resulted in heavy casualties for the USAAF bombers. The German fighters were becoming increasingly heavily armed to deal with the American "heavies". Some German fighters were fitted with heavy armament upgrades which were devastating to USAAF bombers. Dornier Do 217 and Ju 88s also joined in, firing air-to-air rockets. When successful, it could cause high loss rates to bomber streams.
During this period the Luftwaffe achieved several victories over the USAAF. The Schweinfurt-Regensburg mission on 17 August 1943 resulted in 36 of the 230 attacking B-17s being shot down with the loss of 200 men. In addition an earlier raid in the day against Regensburg, a total of 60 B-17s were lost that day. Luftwaffe losses stood at around 27 fighters. A second attempt on 14 October 1943, "Mission 115", would later come to be known as "Black Thursday". Of the 291 attacking Fortresses, 77 B-17 were lost. Around 122 bombers were damaged. The German losses amounted to 38 fighters.
Raids had an enormous effect on the German distribution of weaponry. In the summer of 1943, 2,132 Flak guns were protecting German industrial targets. In 1940, the number had been 791 guns. These guns could have been better used at the front. Moreover, it took an average of 16,000 shells for any particular 88 mm gun to shoot down an American bomber. The production of fighters should have been considered a priority, but Hitler and Goring forbade a switch to the production of defensive fighters. Yet, attrition was having an impact on production. Production in July 1943 amounted to 1,263; by December, it had fallen to 687. The reduction was due to American efforts against aircraft factories. In October 1943, German intelligence reported Allied fighter aircraft were reaching as far east as Hamburg. The P-47 and P-38s were fitted with drop tanks to extend their range. Some reached and crashed near Aachen on Germany's west border. General der Jagflieger Adolf Galland brought this to the attention of Göring, who dismissed the event as a fluke. He asserted that the fighters must have been damaged and glided eastward from a great height. The danger was ignored.
From mid-October 1943 until mid-February 1944, when the Big Week Allied bomber offensive was launched, the Luftwaffe had won air superiority over Germany. It was also clear to the USAAF that air superiority could not be regained until sufficient long-range escort became available. The 8AF made no more deep penetrations in clear weather into Germany for the rest of the year. That failure was, prior to December, the result of a command decision based on the lack of escort and the need for recuperating the bomber force after its losses on 14 October.
Limited British success (1942–1943) 
Area offensives 
Bomber Command had a few successes during this time. Introduction of new navigation aids such as Oboe allowed for accurate bombing. The bombing of Cologne in May 1942, the five month-long Battle of the Ruhr and bombing of Hamburg were very successful.
During the Battle of the Ruhr, Bomber Command severely disrupted German production. Steel production fell by 200,000 short tons (180,000 t). The armaments industry was facing a steel shortfall of 400,000 short tons (360,000 t). After doubling production in 1942, production of steel increased only by 20% in 1943. Hitler and Speer were forced to cut planned increases in production. This disruption caused resulting in the Zulieferungskrise (sub-components crisis). The increase of aircraft production for the Luftwaffe also came to an abrupt halt. Monthly production failed to increase between July 1943 and March 1944. A raid on the city of Essen on 8 March 1943 destroyed 160 acres of the city centre and caused 75% destruction in a further 450 acres. Further attacks on the industrial city Kassel dehoused 123,800 people (62% of the population) and killed 6,000. Tiger tank production at the main plant of Henschel was halted for months and 88 mm artillery production was halted for four months. Locomotive production, the Henschel firm's main product, ceased in the Ruhr after July 1943 and production was further disrupted by the destruction of 100,000 workers dwellings. Production of ammunition fuses (for artillery) was also stopped. Some 200,000 had been produced prior from September 1939-March 1943. For the time being "Bomber Command had stopped Speer's armaments miracle in its tracks". Furthermore, some 7,000 heavy German artillery had been diverted to protect the Ruhr. The success was at a price. Some 640 bombers were lost. British and Commonwealth losses were; 2,122 British, 590 Canadian, 150 Australian, 102 New Zealand and two South African casualties.
By early May 1943 the secret of the Lichtenstein B/C radar was out, as a defecting Luftwaffe crew flew a Ju 88R-1 night fighter from occupied Denmark to Scotland, which was equipped with the earliest form of AI radar to be used by the Luftwaffe. A type of Window (chaff) was devised to block the B/C's ability to search for RAF night bombers, bringing on the onset of the Wilde Sau tactics using day fighters during nocturnal intercepts.
The attack on Hamburg in July 1943 was made beyond Oboe range, the RAF bombers instead relying on the first operational use of H2S, but with the use of Window countermeasures which confused German radar defences, only 12 aircraft failed to return and 31 were damaged. Some 306 of the 728 bomber crews hit within three marker point. Figures given by German sources indicate, 183 large factories were destroyed out of 524 in the city, 4,118 smaller factories out of 9,068 were destroyed. Other losses included 580 industrial concerns and armaments works, 299 of which were important enough to be listed by name, were either destroyed or damaged. Local transport systems were completely disrupted and did not return to normal for some time. Dwellings destroyed amounted to 214,350 destroyed out of 414,500. Window had given Bomber Command the tactical advantage, but it was not to last.
German reaction 
After experiencing several 'Window attacks', the Luftwaffe started to change its tactics. With radar neutralised by Window, German night fighters found it difficult to intercept the bombers. However, German ground controllers no longer used to radar sets to guide German fighters and track individual enemy bombers in order to intercept. Instead, they gave a running commentary on the stream as a whole. No individual aircraft were tracked unless caught in searchlights. These changes did not produce immediate success, but pointed the way to a method of loosely controlled cat's eye interception. The success of the new tactics were indicated in increasing bomber losses.
Other tactics were tried. A method known as "Wilde Sau" was used, in which single-engine fighters were supported by searchlights, and using passive radar detector guidance instead of radar, to destroy enemy bombers. Implemented on 26 September 1943 the tactics had limited success suffered high losses in the winter, 1943–1944. Jagddivision 30 (Fighter Division 30), the specialised unit controlling Wilde Sau fighter wings such as JG 300, was disbanded, with the specialized wings later flying regular daytime bomber interceptions instead.
German production was only just keeping pace with night-fighter losses. Some 2,375 aircraft were lost and only 2,613 were built in factories or re-entered the frontlines from repair workshops. The overall numbers fell from 76% of establishment to 63% in 1943. Serviceability fell from 72% to 66%. The battles had also taken a toll of the RAF. The Ruhr battle had cost the RAF 923 bombers, another 813 were lost over Hamburg.
The contribution of RAF Bomber Command to the Allied war effort during this period remains controversial. By the end of 1943, the Nazi leadership had feared that morale would collapse and civil war would ensue. Joseph Goebbels the Third Reich's propaganda minister denounced the air raids as "terror bombing" and sought to rally the people in a bid to improve morale. Albert Speer recorded in his diary that the people had proved Goebbels fears unfounded. Morale was improving, and the RAF had failed, and was failing to break morale. However, after the war, the United States Strategic Bombing Survey concluded that morale fell. Some 75% of the German population now believed the war was lost owing to the failure of the Luftwaffe to stop the bombing.
Turn of the tide (1944) 
Reorganising the Luftwaffe 
The reported appearance of USAAF fighters as far east as Bremen made for uncomfortable reading for the RLV. The defence of Germany took priority over all the territories. Generaloberst Wiese met Adolf Galland's staff in November 1943 and attempted to create a solution to this problem. As it stood, three air divisions were to defend German air space. 3. Jagddivision was the first line of defence, protecting Germany's air space at the French border stretching to Luxembourg and into western Belgium. 1. Jagddivision protected the Netherlands and north west Germany. 2. Jagddivision was responsible for the defence of Denmark and north-central Germany and was based near Hamburg. 4. Jagddivision was to defend the Berlin area and 5. Jagddivision protected central and southern Germany. 3. Jagddivision's C-in-C Oberst Walter Grabmann suggested the following:
- All of the Bf 109 Gruppen should be assigned to engage the U.S. escorts
- Two Gruppen should take-off ahead of the main interception force to disperse the escort
- The more heavily armed Fw 190 Gruppen would be directed to the bomber fleets after the bombers had been "stripped of their escorts".
Wiese issued two further orders:
- The Zerstörer Bf 110 and Ju 88 units would only attack if the bombers had been deprived of their escort as described above
- The Zerstörer were permitted to attack if the bombers penetrated beyond the range of their fighter escort.
At this time, the importance of home defence was recognised and Luftwaffenbefehlshaber Mitte was renamed Luftflotte Reich (Air Fleet Reich). Wiese was removed from command and the more experienced aviator Hans-Jürgen Stumpff was appointed as its commander.
The USAAF reorganise 
My personal message to you – this is a must – is to destroy the enemy air force wherever you find them [it], in the air, on the ground, and in the factories.
General Eaker was removed from command and Lieutenant General Carl Spaatz was given command of the USAAF Strategic Air Forces in the ETO. James H. Doolittle was given command of the 8AF and on 21 January he ordered that the German fighter force was to be destroyed as a prelude to D-Day, the Allied landing in Normandy. To do this Doolittle had stated that the Luftwaffe could only be destroyed by attrition in the field.
General Eaker was re-assigned as Commander-in-Chief of the Mediterranean Allied Air Forces. Among the considerable forces under his command were the U.S. Twelfth and Fifteenth Air Force (12AF and 15AF) operating from Italy.
American daylight supremacy 
Doolittle began his campaign to destroy the Luftwaffe during Big Week, from 20–25 February 1944, as part of the European strategic bombing campaign. The USAAF launched Operation Argument, a series of missions against German targets that became known as "Big Week". The planners intended to lure the Luftwaffe into a decisive battle by launching massive attacks on the German aircraft industry. By defeating the Luftwaffe, the Allies would achieve air superiority and the invasion of Europe could proceed. The daylight bombing campaign was also supported by RAF Bomber Command, when they operated against the same targets at night.
The 15AF lost 90 bombers, the 8AF lost 157 bombers and RAF Bomber Command lost another 131 bombers. The 8AFs strength had dropped from 75% to 54%, and the strength of its fighter units had dropped from 72% to 65%. The Luftwaffe's RLV (Reichs-Luftverteidigung) had lost 355 fighters and its operational strength shrank to 50%. The RLV also lost nearly 100 valuable fighter pilots. While Spaatz claimed it as a victory, the production of German fighters dropped only briefly. Nevertheless, the attritional battle would only get worse for the Luftwaffe. After Big Week, air superiority had passed irrevocably to the Allies.
One of the most important developments of "Big Week" was the introduction of the P-51 Mustang. It had the range to escort the USAAF bombers to the target and back again. It also had the performance to engage any piston-engine German fighter in service and the firepower of six Browning .50 in (12.7 mm) AN/M2 machine guns with which to destroy them. The number of Mustangs increased from February 1944 onwards. The rapid re-equipment of USAAF fighter squadrons enabled the new commander of the 8th AF, Jimmy Doolittle, in March of 1944 to send out Mustang squadrons in formations well ahead of the lead elements of the bomber formations, to perform air supremacy "fighter sweeps" to clear the German skies of the Luftwaffe, and permit the USAAF's bombers to operate without serious opposition.
With such serious Allied fighter opposition, the Luftwaffe was put under severe pressure in March–April 1944. According to a report made by Adolf Galland, General der Jagdflieger, on 27 April 1944, 500 aircraft and 400 pilots had been lost in the 10 previous operations. Galland also said that in the previous four months 1,000 pilots had been killed. Galland reported that the enemy outnumbered his fighters between 6:1 and 8:1 and the standard of Allied fighter pilot training was "astonishingly high". Some 25% of the German fighter pilot force had been lost in May 1944 alone, while 50% of the available fighters were also each month from March–May 1944. Galland recognised the Luftwaffe was losing the attrition war and pushed for a focus on quality rather than quantity. Galland stated in his 27 April report, "I would at this moment rather have one Me 262 in action than five Bf 109s. I used to say three 109s, but the situation develops and changes."
The need for technical superiority was evident in the losses in the first half of 1944. In January the Luftwaffe had on strength some 2,283 pilots. It lost some 2,262 between January and May 1944, a 99% loss rate. This helped extend USAAF air superiority over the continent. German losses included experienced personnel. The situation was so serious, Galland remarked:
The strained manpower situation in the air defence of the Reich demands urgently the further bringing up of experienced flying personnel from other arms of the service, in particular for the maintenance of fighting power to the air arm, tried pilots of the ground-attack and bomber units, especially officers suitable as formation leaders, will now also have to be drawn upon.
It was a vicious circle. In order to meet frontline requirements training time was cut. Shorter training hours meant a poorer quality of pilot, which in turn increased the likelihood of a pilot being killed in action. The offensive against Axis oil production was forcing a cut in training time was making things even worse.
The position of the Luftwaffe continued to deteriorate throughout 1944. As German territory contracted the number of AAA guns rose. In November–December 1944, the FlaK defenses were more effective at shooting down Allied bombers than the Luftwaffe. One such example indicates that during sustained attacks on the synthetic oil targets inside the Ruhr, 59 USAAF bombers were lost to AAA, while just 13 were lost to German fighters. Heavy AAA did reduce the bombing accuracy as well as acting for a guide for German fighters searching for the bomber stream. Losses reached an all-time high on 26 November, when intercepting a raid, the RLV lost 119 fighters, 60 pilots killed and 32 wounded for just 25 USAAF fighters and six bombers.
Night war: technological battle 
In the first six months of 1944, unlike the USAAF, RAF Bomber Command's offensive was struggling against the renewed German efforts to outsmart the British in the technological war. Bomber Command had introduced Window, known to the Germans as Düppel, consisting of small aluminium strips would be dropped by formations to blanket German radar and make it difficult for the defenses to pick out the real position of the raiders. To reduce losses further, Bomber Command shortened its attacks over the target by five minutes to reduce chances of interception. This was followed by spoof routes, used to feint the routes of attacks. Later the use of "Mandrel" airborne jamming screens were used to send the enemy into the wrong area and deny the German fighters the chance of reaching the target area in sufficient strength.
The German response was to increase the efficiency of overland plotting systems. The German Observer Corps was essential to this move initially until the introduction of the Wassermann and Mammuth long-range radar became available in large quantities and plotting became centralized and simplified. The Germans also used intercept stations to listen to and track the IFF devices when they were switched on in British bombers over German-held territory. When Bomber Command issued orders to keep these turned off the Germans tracked "Monica" and "H2S" transmissions from British bombers. H2S was tracked by Naxos radar detectors while Monica was tracked on Flensburg radar detectors, both mounted on night fighters. The British refused to believe tracking H2S transmissions was possible, despite Ultra reports identifying these new radar systems and calculating that they were responsible for 210 of the 494 bombers (42 percent) lost over Germany in January to February 1944.
The Luftwaffe's introduction of Lichtenstein SN2 airborne radar was an attempt to produce a set invulnerable to jamming. It came into wide usage between autumn 1943 and the beginning of 1944. The methods quickly caused trouble for Bomber Command. The plotting system was quickly proven and was a formidable defence with few weaknesses. In spite of spoof raids which continued to divert German fighter units and reducing losses, the new system was capable of inflicting 8–9% losses against each raid. German night fighter losses amounted to an acceptable 664 aircraft during 1944 operations.
Technological developments of the Luftwaffe had a considerable impact on operations in the first half of 1944. Harris' new offensive, which culminated in the Battle of Berlin suffered heavy losses and failed to win the war outright, as Harris had expected. The plan was to break German morale at a projected cost of 500 bombers. The mission failed, moreover costing Bomber Command 1,128 bombers compared to German losses of just 256 fighters. Harris sought to reduce losses by introducing the de Havilland Mosquito night fighter to protect the bombers. Instead, the Bristol Beaufighter was selected which proved inadequate until eventually being replaced by the Mosquito. In the air, technology and tactics favored the fighter. Unfortunately for the Luftwaffe, RAF intelligence discovered the uses of Monica, Naxos and Flensburg and curtailed their use of H2S, rendering these three German radar methods far less effective.
Erosion of Kammhuber line 
The Allied liberation of France and most of the low countries in 1944 greatly enhanced the bomber offensive. The Allied Armies overran most of the early warning systems of Kammhuber line. Until then, the night fighters had succeeded in inflicting an overall rate of loss on Bomber Command aircraft attacking targets in Germany — exclusive of bomber support, Mosquito and mine laying operations — amounting to 3.8% in July 1944, and on one night — 28–29 July — 8.4% of the force was lost, though this was attributed to the "unusual lightness of the night". Added to this was the growth of German night fighter forces which grew from 550 aircraft in July 1943 to 775 in July 1944.
But the Luftwaffe was also suffering. It was forced to combat the threat although it could not afford the man or material power losses. While their losses were far smaller than those of the British, the crews also suffered through bad weather, low-level skill and a high accident rate due to night flying. In the first three months of 1944, it lost 15% of its crews. The introduction of Mosquito night fighter variants caused problems for the Nachtjagdgeschwader. The Mosquito proved superior in performance to most German night fighters and it is rumoured that German pilots were credited with two kills for shooting one down. Between 1943 and 1945, German night fighters shot down only 50 Mosquito aircraft of all types.
Tactical problems were just some of the difficulties facing the German night defences. The campaign against German oil industries in 1944 would cause serious issues for the service. After August 1944, the German night fighter force did not have enough fuel to train new crews or operate effectively. After this date, it ceased to pose a threat to Bomber Command.
Impact on German production 
The campaigns of 1944 and the superiority of USAAF formations over Germany created problems for the German war effort. In response to this development, German industries were forced to disperse their production. The official order was given in February 1944, following Big Week. Some 27 main plants were dispersed into 729 smaller ones. When the war ended, the number of small plants aircraft production had been moved to numbered 300. Engine plants were dispersed at 249 locations from the original 51 large plants.
The cost and difficulty of spreading production around increased. The railways now carried an extra burden moving material around which made production reliant on rail. During the communication attacks by Bomber Command in late 1944, this weakness would see German production curtailed. A lack of technical advisors was now experienced. Spreading plants around in multiple locations created a shortage of technical personnel at various locations. More workers, a 20% increase, were need to facilitate transportation, which in turn competed with the demand from the Army and the need for manpower elsewhere. The bombing and dispersal of plants also damaged efficiency of jig building. The additional loads taken on in order to 'tool up' new locations, multiplied many times over, created a bottleneck. It explains, despite the increased overall production, the failure of German factories to meet planned production in 1944.
Oil campaign (May–November 1944) 
Spaatz' strategy 
As mounting evidence, from all sorts of intelligence sources and from observation of ground movements, indicated that the Germans were suffering desperate local shortages, the tactical air forces intensified their attacks on oil trains and storage dumps near the front lines. The Eighth and Fifteenth Air Forces showed improvement in the use of H2X radar devices, and RAF Bomber Command was employing Gee-H to better advantage as its crews became more experienced. It was discovered that synthetic oil plants lent themselves to successful air attacks more easily than oil refineries, since the former could be put out of action by relatively small damage to critical parts of their complicated machinery. Furthermore, the synthetic plants were much larger than the refineries and were more likely to appear on radar screens because they usually stood some distance outside of cities. The 15AF sharply raised its level of accuracy and developed techniques, such as the use of diamond-shaped formations, which ensured more safety for the bombers as well as greater precision in attack.
A further strengthening of the effort came from the Joint Oil Targets Committee set up in London to supervise the oil campaign more scientifically. This organisation, which drew membership from United States Strategic Air Forces in Europe (USSTAF), the British Air Ministry, and the Ministry of Economic Warfare, evaluated methods of attack and checked data from the continent concerning German oil difficulties. One of its first decisions was to recommend intensification of attacks on gasoline production, thus giving highest priority to the synthetic oil plants and to crude oil refineries in Romania, Hungary, Poland, and Germany, in that order. Allied strategic planners recognised German petroleum supplies as the weak link. By 1938, German oil imports accounted for ⅔ of its stocks. As war approached, the Germans resorted to synthetic oil production. IG Farben's coal was converted to oil, in turn this was responsible for all of the Luftwaffe's aviation stocks. On 23 November 1940, the signing of the Tripartite Pact and the addition of Romania and Hungary to the Axis Alliance gave Germany valuable crude oil wells.
The USAAF wanted to make oil a priority target. In the late spring 1944, it had the long-range fighters to protect the bombers launching sustained attacks on the oil production centres at Ploieşti. At this time, the USAAF had conflicting priorities; the combined bomber offensive, operation Pointblank, and the tactical support of Allied armies in Normandy.
Spaatz and Harris once again protested at the use of their services for tactical support, each with their own agendas and targets. Harris wanted to continue his policy of area bombing industrial cities, Spaatz wanted to attack the oil plants. Both believed their strategies would cripple the German war effort. Spaatz threatened to resign if at least one of the strategic bomber forces was not given over to a campaign against oil targets. He argued bombing tactical targets in France was pointless, as rail yards could be easily repaired. Moreover, he wanted to provoke the Luftwaffe in battle. Spaatz thought that attacking rail targets would not achieve this, but striking at Petroleum would. Eisenhower relented, and Spaatz succeeded in moving the USAAF 15AF to Romanian targets. Up until this point, only sporadic attacks had been made against oil targets.
The Luftwaffe's position 
The OKL faced two major challenges at this juncture. The first was the reinforcing of Luftflotte 3 from Luftflotte Reich, to deal with the imminent Allied invasion of France. The second was protecting the Reich's airspace from ever deeper penetrations by the USAAF.
The tactical situation offered a glimer of hope. The Messerschmitt Me 163 rocket powered fighter and the Messerschmitt Me 262 jet fighter started to enter service in small numbers, with the specialist rocket fighter wing named JG 400, and the Erprobungskommando 262 test unit respectively, with the Jagdgruppe-sized Kommando Nowotny taking over the deployment of the 262 after summer had ended.
The newly designated Sturmgruppen consisting of the Fw 190A-8/R2 Sturmbock was also entering service with Jadgeschwader, which was allocated to defend Romania. The A-8/R2s armament consisted of two 30 mm MK 108 cannons, one per gun pod under each wing, which could destroy a B-17 with three hits, and shoot down a B-24 with a single hit. The Fw 190A-8/R2 had been armoured and was largely invulnerable to American defensive fire. However, the same attributes that made them deadly "bomber killers", damaged the Fw 190's already limited performance at high altitude, as the fighter became slower and unwieldy. Like the twin-engine Ju 88s, Bf 110s and Me 410s, they would need escorting by Bf 109-equipped units.
Battles over the oil fields 
On 12 May 1944, the first USAAF raid, as part of this deliberate systematic campaign on the oil industry began. Its results were dire for the Germans; "12 May 1944, can fairly be described as the worst single day of the war for Germany. Other days brought dramatic defeats, and terrible casualties, but never without the possibility of a reversal of fortune". Albert Speer wrote, "The enemy has struck us at one of our weakest points. If they persist at it this time, then we will soon no longer have any fuel production worth mentioning".
Following the ruinous attacks on oil in April–May 1944, the Germans began to experiment with a new defensive measure, one which proved very satisfactory to them for some time. Whenever their warning system indicated the approach of air fleets over Yugoslavia toward Romania, the Germans would use the 40 minutes available to them before the attack to light hundreds of smoke pots around the Ploesti fields, with the result that most of the area would be concealed by the time the bombers arrived. Thus precision attack was impossible. In an effort to overcome this obstacle, the 15AF dispatched on 10 June 1944, not bombers, but P-38's, to drop 1,000-pound bombs at low-level while others gave cover. At best this experiment was only an equivocal success. The oil situation remained serious for the German defenders. Göring ordered an immediate economy on the use of fuel and large numbers of AAA units were moved from the cities and sent to guard the oil fields.
RAF Bomber Command played a more important role in the oil campaign than is usually recognised. It dropped 93,641 short tons (84,950 t) on these targets, compared to the combined total (from both the 15AF and 8AF) of 119,420 short tons (108,340 t). It dropped more tonnage than the 8AF (48,378 short tons (43,888 t)) operating from the same area of Britain. The RAF's main target was the synthetic oil targets in the Ruhr.
The Luftwaffe was now in an impossible position. The oil industry had to be defended, but doing so was costly. I. Jagdkorps was losing fighters at a rate of 10% per mission, while the American bomber losses were only at two percent. By September 1944, the loss to kill ratio was against the Luftwaffe. With some exceptions, the loss rate for Allied formations remained under one percent, the German losses were lying between 10 and 20%. The Allied formations were 18 times larger than the Germans by this stage, which meant the respective loss ratios would indicate a higher loss for the German defenders. However during September the actual kill count of the RLV during September 1944 was 307 shot down for 371 losses. By October 1944, serviceable aircraft amounted to just 347, excluding units on conversion training. The 15AF continued to operate on an impressive scale. During the latter part of the summer its twenty daylight missions against Ploiești, with the aid of the four night missions flown by the RAF, would deny the Germans an estimated 1,800,000 short tons (1,600,000 t) of crude oil.
The USAAF and RAF Bomber Command flew hundreds of missions against the oil targets until late August. The main refinery, in Romania, was virtually destroyed by the bombing. The final raids made against Ploesti were made by 15AF on 19 August 1944. The Romanians, and the Romanian Air Force which had fought alongside the Luftwaffe thus far, capitulated to the advancing Red Army on 23 September and declared war on its former ally. The remaining German fighter units retreated into Yugoslavia and Hungary. The Slovak Air Force and Hungarian Air Force continued to support the Luftwaffe by defending targets in central Europe into 1945.
Bomber Command and the Ruhr plants 
RAF Bomber Command struck at synthetic targets in the Ruhr districts until November 1944, when the Combined Chiefs of Staff concluded that the oil plants had been reduced to the extent that further attacks were wasteful. Harris was ordered to cease attacks and shift to communications target. Air Chief Marshal Portal demanded that the British share the losses the 8AF had been taking by assuming responsibility for two of the largest and most distant targets, Pölitz and Merseburg-Leuna.
The crippling of Germany's warning system in the west as a result of the Allied victory in France and the increased efficiency of blind-bombing techniques made such RAF missions possible, and they proved generally successful. Speer subsequently reported to Hitler that the night attacks were more effective than the daylight missions, because heavier bombs were used and greater accuracy had been attained. On the average, British operation against oil targets during the autumn, 660 short tons (600 t) fell as compared with 388 short tons (352 t) for a USSTAF mission. Germany's oil production for November was estimated at 31% of the monthly average in the preceding spring, with most of the supply coming from the benzol plants, which had not been regarded as worth attacking until the autumn. Pölitz and Merseburg-Leuna were listed as heavily damaged but in partial operation. All of the synthetic plants in western Germany, however, were reported out of action and the crude refineries around Hamburg, Bremen, and Vienna as functioning only on a small scale. In fact, the evidence indicated that only one sizable crude-oil refinery was operating in Germany. Since the beginning of the oil offensive the 15AF had dropped 45,000 short tons (41,000 t), the 15th Air Force 27,000 short tons (24,000 t), and Bomber Command 22,000 short tons (20,000 t) on oil-producing targets.
Effect on Luftwaffe training 
|Year||Germany||United Kingdom||United States|
The attacks were having a devastating effect on German fighter units. More and more Staffeln and Gruppen were pulled off the front line on the Eastern Front to reinforce the Reich. Göring ordered that more effort be made to train pilots more thoroughly and quickly whilst expanding the Jagdflieger force. He ordered bomber pilots to be converted to fighter pilots. This failed. Pilot training was shortened to meet the need for pilots. In 1944, the pilot programme had shrunk to eight months and 111 flying hours; just 20 hours on the Fw 190 and Bf 109. This was less than ½ of what the German cadets could receive in 1942.
German fighter pilot schools relied on fuel. They required 60,000–80,000 short tons (54,000–73,000 t) per month. With this achieved, they claimed to be able to train 1,200 fighter, 250 ground-attack, 40 bomber, 75 jet-bomber, 64 recce and 40 night fighter pilots a month. The schools demands were never met. Just 13,500 short tons (12,200 t) were delivered in July 1944, 13,400 short tons (12,200 t) in August and 6,300 short tons (5,700 t) in September. There were plenty of cadets joining, but the primary schools had to be shut down in favour of running the advanced flight schools. The influx of bomber pilots helped keep output high but it was not to last. By the autumn, the Luftwaffe was seeking anyone who already had basic experience in flying, so they could bypass the primary stages of flight school.
In pre-war establishments, and up until 1942 the German training programs had proven better in terms of training time given to pilots than the Allies. However, German training time reduced through the war, while Allied training improved. The decrease in skill and training was caused by the attrition rates of pilots and skilled aircrew. This was perhaps the most important aspect in the decline of the Luftwaffe and an effective fighting force. The rise in attrition caused a steady decline in skills and experience forced the Germans to curtail training programs to fill empty cockpits. Owing to this, new pilots with less skill than their predecessors were lost at a faster rate. The increasing losses, in turn, forced the training establishments to produce pilots even more rapidly. Once this cycle began, it was difficult to escape. One of the key indicators in the decline of German fighter pilot skill after 1940 air battles was the rise of losses owing to non-combat causes. By the first half of 1943 losses sustained in accidents were as many as losses in combat.
Impact on Axis oil production 
The oil campaign was hugely successful. In June 1944, just 56,000 short tons (51,000 t) of oil had been produced against the planned total of 198,000 short tons (180,000 t). Consumption was well above stocks produced since mid-May 1944 so that by the end of June 1944, it had been reduced to a reserve of just 410,000 short tons (370,000 t), a 70% reduction from 30 April 1944. ULTRA intercepts confirmed cutbacks in non-operational flying as a direct consequence. According to Speer, by 21 July 98% of all Axis fuel plants were out of operation. The monthly production fell from 180,000 short tons (160,000 t) in March 1944 to 20,000 short tons (18,000 t) in November; inventory dropped from 575,000 short tons (522,000 t) to 175,000 short tons (159,000 t). The campaign caused huge shortfalls in fuel production and contributed to the impotence of the Luftwaffe in the last 10 months of the war, and the inability of the German Army to conduct counter offensives.
Collapse of German communications (Autumn 1944) 
Decline of night defences 
The effectiveness of Nachtjagdgeschwader units was deteriorating. In 1943-1944, it had proved the most efficient branch of the Luftwaffe. Even as late as July 1944, it was scoring successes. But in August, fuel shortages caused a curtailing operations. From that date, the Nachtgeschwader failed to make a serious impact on the night offensive.
The lack of fuel was one factor. Another was the Allied advance across western Europe which deprived the Germans of their early warning systems for detecting incoming raids. Supplementing this were the countermeasures introduced by RAF Bomber Command, such as intruder operations in which Mosquito night fighters would attack German fighters as they took off from and returned to base. This compelled the Germans to restrict the use of airfield lighting and assembly beacons. Owing to fuel shortages, training of night crews was not as thorough as before, while the demands of manpower throughout the Wehrmacht had brought about a decline in quality in the servicing and ground staff. Some of the fighter force had to withdrawn to the Eastern Front to counter night attacks by the Soviet Red Air Force. Nevertheless, its strength increased: from 800 to 1,020 between 1 July and 1 October 1944, of which 685 in July and 830 in October were engaged in operations against RAF Bomber Command.
In late 1944, the German defensive line now only extended from Denmark to Switzerland. This enabled British bombers to fly toward German territory without interception on the way. The German strength was thus reduced, with more aircraft diverted to reconnaissance over the North Sea in an attempt to pick up Allied bomber formations. In spite of the problems, the Luftwaffe night fighter force was stronger numerically than ever before. It remained intact and presented a theoretical threat to Bomber Command, particularly when the British made deep penetrations. However, since the first half of 1944, the outlook for the force had changed from increasing efficiency to a probability of declining effectiveness as the cumulative effect of poor training, shortage of fuel, diversion of effort and shortage of manpower became perceptible.
Bomber Command: Transportation plan 
In the last year of the war, the bombing offensive "came of age". With German defences strategically defeated, the economy was exposed to enormous bombing attacks. Most of the tonnage dropped by the American and British bomber fleets was done so in the last year of the war — some 1,180,000 short tons (1,070,000 t) from 1,420,000 short tons (1,290,000 t) during the entire war. The attacks did not go entirely unopposed. There were 50,000 heavy and light German anti-aircraft guns concentrated around essential industrial targets. There remained an "exiguous fighter force by day and night".
The USAAF could throw 7,000 bombers and fighters into the battle while the RAF could field 1,500 heavy bombers which could carry up to 20,000 lb (9,100 kg) of bombs. By the autumn of 1944 Allied fighter-bombers and fighters could strafe and engage targets untouched. This firepower was aimed at the Ruhr industrial heartland and the communication networks in Germany. The rail lines were mostly destroyed, halving coal and material traffic by December 1944 compared to the previous year. With the loss of the Romanian oilfields in August 1944, the campaign critically reduced German oil supplies and production remaining. In the winter of 1944–1945, the German state was carved into isolated economic regions living off accumulated stocks while aircraft production was to be moved under ground into caves, salt mines and underground factories manned by slave labourers. The conditions underground were far from ideal. Poor ventilation and high humidity damaged precision machinery and tools which made the quality of production poorer. In salt mines, the walls absorbed the moisture and eased conditions. The logistical difficulty of locating several thousand workers well over 1,000 ft (300 m) below ground level interfered with production.
The effectiveness of attacks on rail and communications began in the autumn 1944. The Luftwaffe could not prevent the destruction of the city Kassel's electricity supply ending Krupp Gusstahlfabrik (Cast Steel Works) contribution to the war on 23 October 1944. This type of direct attack was unable to stop production altogether. Attacks on communications came closest to achieving this goal. The Dortmund-Ems canal was drained by an attack in September 1944. The huge marshalling yard at Hamm was damaged and its capacity reduced by 75%. Between 14 and 18 October, the rail shipments of coal from the Ruhr ended completely. By early October 1944, only one train in 50 was getting into the Ruhr in the first place. The lack of iron ore caused a drop in steel production of 66%. Some 102,796 short tons (93,255 t) had been dropped on these targets. It was enough to bring near total collapse between November 1944 and January 1945.
The statistics point to the gradual strangulation of the German transport system. The daily average of freight car tonnage dropped from 183,000 in June 1944 to 83,000 in December 1944. Waterborne movements of coke and coal from the Ruhr declined from a daily average of 76,000 tons in July 1944 to 14,200 by January 1945. Stocks of coal, the main source of power for German industry, rose from a low of 186,000 tons kept at the mineheads in July 1944 to 2,767,000 tons in February 1945. The rise in tonnage demonstrates the collapse of the transport network, which meant raw materials could not be transported or moved effectively from the mineheads to the factories. It is estimated that production fell by 22 percent between May 1944 and January 1945. Of this reduction, some 50-60% of this was due to attacks on transportation.
Defeat (1945) 
Daylight defence 
When 1945 began, the Allies were on the German borders, and in some places had captured German towns such as Aachen. With the territory under German control contracting and Germany's territory itself in the frontline, the distinction between tactical and strategic attack blurred. Allied air forces and the Luftwaffe found themselves providing support over the frontline while battling to attack or defend industrial targets.
Hitler attempted to improve Germany's continually worsening military position by launching operation Wacht am Rhein (Battle of the Bulge). The RLV handed over some Jagdgeschwader to support the offensive along with the Luftwaffe's frontline fighter units. The cost was high, some 400 pilots were killed or missing between 16–31 December 1944. On 1 January 1945 the Luftwaffe launched Operation Bodenplatte in a bid to win back air superiority and help restart the German offensive, which was now in trouble. The Luftwaffe committed over 900 fighters to the operation. It failed, effectively destroying the remaining core of the Luftwaffe.
The Luftwaffe's senior staff had hoped that projects like the Me 163 rocket fighter or Me 262 jet fighter would be given priority as a bomber interceptor as early as 1942. However, problems with jet engine development and Hitler's insistence the Me 262 be used as a strike aircraft, and problems with its engines, hampered its development and delaying its entry into the RLV. The operations of the Me 262 and Me 163 did little to offset the problem of Allied air superiority. German losses remained high due to the difference in fighter pilot training. On 7 April 1945, for example, only 15 of 183 Fw 190s and Bf 109s which were covered by a large force of Me 262s, returned to base from an interception sortie. The Germans reported the loss of 133 fighters, claiming 50 of the USAAFs bombers in return. In reality, only eight American bombers were shot down.
During this period the Western Allied invasion of Germany had already begun. Airfields and bases that were located in Western Germany were quickly overrun. The Luftwaffe defended its airspace continually, but suffered heavy losses flying defensive and offensive sorties over the Allied bridgeheads that were established along the Rhine River. A few successes were scored, and some missions, including forces of up to 40-50 Me 262s were used, but the losses inflicted on the bombers were not decisive. The Allied Air Forces had total air superiority and attacked the Luftwaffe on the ground and in the air. In just two days, 13–15 April, 400 German fighters were lost to Allied ground attack fighters.
End of the Area offensives 
The intensifying campaign against German cities did not cease. Among the most controversial raids was the Bombing of Dresden in February 1945. The rationale of the raid was to aid the advance of the Red Army on the Eastern Front. Dresden was a communications hub which, it was believed, was transporting German reinforcements to eastward. It was also thought it harboured significant industries in and around the city. Its value as a military target was and still is questioned due to the cities apparent lack of industrial potential in its centres and the late stage of the war. Soon afterwards, Allied forces conducted Operation Clarion. The operation sent thousands of bombers and fighters by day and night to target smaller cities and targets of opportunity.
Attacks on other targets took place in March–April 1945. On 19 April, the Combined Chiefs of Staff issued a directive that stipulated all further operations by strategic air forces should be diverted to land-support duties. It came into effect on 5 May. On 26–27 April, the USAAF flew their last operations. Bomber Command, by that time, was busy supporting the Army by flying out Allied prisoners of war.
On 8 May, Nazi Germany capitulated, ending the fighting in the European Theatre of World War II.
See also 
- The scope of the Defence of the Reich campaign grew over time. By July 1944, it included: Germany, East Prussia, Austria, Czechoslovakia, Denmark, Netherlands, Belgium, central eastern, and north eastern France, Poland, Hungary and Lithuania. Boog 2001, pp. 216-217. (German language version)
- Boog 2001, p. 180 and Hooton 1997, p. 284. Figures are for 1943 and 1944 only. Boog gives the loss of "8,286 defensive aircraft" in 1943 and Hooton gives 3,706 day fighters and 664 night fighters for 1944. Added are 2,634 day and 142 night fighters lost in "Western Sorties" in 1944.
- Caldwell & Muller 2007, p. 9.
- Beaumont 1987, p. 13.
- MacIsaac 1976, p. 9.
- Frankland and Webster (Vol 3) 2006, p. 276.
- Frankland and Webster (Vol 3) 2006, p. 268. Figures for June to December 1944.
- Frankland and Webster (Vol 2) 1961, p. 253. Figure given in footnote: Period October 1943 to July 1944.
- Cox 1998, p. 115
- Caldwell & Muller 2007, p. 42.
- Murray 1983, p. 132.
- Overy 1980, p. 409.
- Caldwell & Muller 2007, p. 43.
- Caldwell & Muller 2007, p. 46.
- Caldwell and Muller 2007, p. 288.
- Caldwell and Muller 2007, p. 286.
- Caldwell and Muller 2007, pp. 285-286.
- Caldwell and Muller 2007, pp. 285, 287.
- Caldwell and Muller 2007, p. 287.
- Hooton 2010, p. 38.
- Caldwell & Muller 2007, pp. 287-288.
- Murray 1983, p. 133.
- Overy 1975, p. 786.
- Murray 1983, p. 138.
- Murray 1983, p. 139.
- Murray 1983, pp. 253–255.
- Overy 1980, p. 107.
- Overy 1980, p. 106.
- Caldwell & Muller 2007, pp. 34–35.
- Koch 1991, p. 127.
- Koch 1991, p. 124.
- Caldwell & Muller 2007, p. 31.
- Caldwell & Muller 207, pp. 36–37.
- Caldwell & Muller 2007, p. 40.
- Overy 1980, p. 108.
- Overy 1980, p. 110.
- Hooton 1997, p. 121.
- Hooton 2010, p. 92.
- Hooton 1997, pp. 122-123 and Hooton 2010, p. 92.
- Hooton 1997, p. 123.
- Hooton 1997, p. 122.
- Hooton 1997, p. 125.
- Hastings 1979, p. 235.
- Caldwell & Muller 2007, p. 44.
- Murray 1983, p. 177.
- Hall 1998, p. 113.
- Hall 1998, p. 114.
- Hall 1998, p. 115.
- Hall 1998, pp. 115-117.
- Hall 1998, p. 117.
- Hall 1998, p. 118.
- Caldwell & Muller 2007, p. 49.
- Caldwell & Muller 2007, p. 50.
- Murray 1983, p. 172.
- Frankland and Webster 1961, p. 27.
- Frankland and Webster 1961, p. 22-24.
- Frankland and Webster 1961, p. 30.
- Frankaland and Webster 1961, p. 37.
- Caldwell & Muller 2007, p. 51.
- Cooper 1981, p. 193.
- Caldwell & Muller 2007, pp. 51–52.
- Cladwell & Muller 2007, p. 52.
- Cooper 1981, p. 266
- Caldwell & Muller 2007, p. 68.
- Boog 2001, p. 164.
- Caldwell & Muller 2007, p. 70.
- Caldwell & Muller 2007, p. 71.
- Caldwell & Muller 2007, p. 77.
- Caldwell & Muller 2007, p. 81.
- Caldwell 1994, p. 96.
- Craven and Cate 1983 (Vol 2), p. 699.
- Price (2005), p. 129
- Bowman & Boiten (2001), p. 64
- Jablonski (1974), p. 186
- Caldwell & Muller 2007, p. 137.
- Murray 1983, p. 190.
- Murray 1983, pp. 229-231.
- Craven and Cate 1983 (Vol 2), pp. 705-706.
- Frankland and Webster (Vol 2) 1961, p. 118.
- Tooze 2006, p. 601.
- Boog 2001, p. 52.
- Cooper 1992, pp. 134-135.
- Tooze 2006, p. 598.
- Cooper 1992, p. 44.
- Cooper 1992, p. 142.
- Frankland and Webster (Vol. 2) 1961, p. 152.
- Frankland and Webster (Vol 2) 1961, p. 262.
- Frankland and Webster (Vol 2) 1961, p. 200.
- Frankland and Webster (Vol 2) 1961, p. 153.
- Frankland and Webster (Vol 2) 1961, p. 154.
- Boog 2001, p. 165.
- National Archives 2000, p. 279.
- Boog 2001, p. 185.
- Murray 1983, p. 220.
- Hastings 1979, p. 232.
- Hastings 1979, p. 233.
- Kershaw 1987, p. 206.
- Caldwell & Muller 2007, p. 119.
- Caldwell & Muller 2007, p. 140.
- Caldwell & Muller 2007, p. 146.
- Caldwell & Muller 2007, pp. 149–150.
- Hess 1994, p. 73.
- Caldwell & Muller 2007, p. 162.
- Caldwell & Muller 2007, p. 163.
- Gerbig 1975, pp. 28–30.
- Caldwell & Muller 2007, p. 189.
- Caldwell & Muller 2007, p. 188.
- Cox and Grey 2002, p. 103.
- Murray 1983, p. 240.
- Murray 10983, p. 243.
- Murray 1983, p. 245.
- Boog 2001, p. 126.
- Caldwell & Muller 2007, pp. 247–248.
- Caldwell & Muller 2007, p. 253.
- Hooton 1997, p. 259.
- National Archives 2000, p. 280.
- Hooton, 1997, p. 284.
- Hooton 1997, p. 261.
- Hooton 1997, p. 262.
- Frankland and Webster (Vol 2) 1961, pp. 139-141.
- Price 1991, p. 56.
- Murray 1983, p. 221.
- Gerbig 1975, p. 130.
- Hastings 1979, p. 240.
- Boog 2006, p. 166.
- Hall 1998, p. 145.
- MacIsaac 1976 (Vol II), p. 23.
- MacIsaac 1976 (Vol II), p. 24.
- MacIsaac 1976 (Vol II), p. 25.
- MacIsaac 1976 (Vol II), p. 26.
- Craven and Cate 1983 (Vol 3), p. 286.
- Caldwell & Muller 2007, p. 190.
- Caldwell & Muller 2007, p. 191.
- Caldwell & Muller 2007, p. 195.
- Caldwell & Muller 2007, p. 198.
- Craven and Cate 1983 (Vol 3), pp. 281-283.
- Biddle 2002, p. 237.
- Hall 1998, p. 167.
- Hall 1998, p. 157.
- Price 1973, p. 138.
- Caldwell & Muller 2007, pp. 201–202.
- Gerbig 1975, p. 17.
- Gerbig 1975, p. 18.
- Gerbig 1975, p. 19.
- Craven and Cate 1983 (Vol 3), pp. 295-297.
- Cladwell & Muller 2007, p. 226.
- Caldwell & Muller 2007, p. 229.
- Caldwell and Muller 2007, pp. 198, 210.
- Craven and Cate 1983 (Vol 3), p. 645.
- Craven and Cate 1983 (Vol 3), pp. 645-46.
- Murray 1983, p. 314.
- Caldwell & Muller 2007, p. 204.
- Caldwell & Muller 2007, p. 205.
- Murray 1983, p. 303.
- Murray 1983, p. 312.
- Cooper 1981, p. 349.
- Hall 1998, p. 144-145.
- National Archives 2000, p. 365.
- National Archives 2000, p. 368.
- Murray 1995, p. 125.
- MacIsaac 1976, PP. 27-28.
- Tooze 2002, p. 650.
- Hall 1998, p. 160.
- Caldwell & Muller 2007, p. 261.
- Parker 1998, p. 447.
- Manhro & Putz 2004, pp. 272–273.
- Price 1993, p. 176.
- Gerbig 1975, p. 138.
- Gerbig 1975, p. 139.
- Biddle 2002, pp. 254-257.
- Biddle 2002, p. 260.
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