Before April 1916, the German Army's Military Aviation Service, (Die Fliegertruppen des deutschen Kaiserreiches) which had existed since 1912, was largely organised in small general purpose units (Feldfliegerabteilung) - although the formation of the first specialised bombing and close support units had begun during 1915. The Feldfliegerabteilung were completely subservient to the Army command to which they were attached.
In the aftermath of the Battle of Verdun - during which the German side lost the air superiority built up during the so-called Fokker Scourge, and in particular, as a result of the superior performance of the Royal Flying Corps during the Battle of the Somme, a complete reorganisation of the German flying service took place. It was greatly expanded, renamed the Deutschen Luftstreitkräfte (reflecting a far greater degree of autonomy, although it remained an integral part of the army), and acquired a far greater number and variety of specialist units, including the first single-seater fighter units in German service, the Jagdstaffeln (literally, "hunting squadrons").
By the end of the spring of 1915, the pre-production examples of the first German fighter aircraft — the five examples of the Fokker M.5K/MG, and the earliest examples of the production Fokker E.I — had initially been issued in small numbers to various ordinary Feldflieger-Abteilungen for escort duties. Such pioneering pilots as Kurt Wintgens, Max Immelmann and Oswald Boelcke pioneered the more aggressive use of the early Fokker Eindecker fighters, but there were no specialist fighter units until1916.
The first step towards homogenous fighter-only aviation units within the German military, was the establishment of Kampfeinsitzer Kommando (KEK, single-seat battle unit) formations by Inspektor-Major Friedrich Stempel in February 1916. These were based around Eindeckers and other new fighter designs emerging, like the Pfalz E-series monplanes, that were being detached from FFA units during the winter of 1915–16 and brought together in pairs and quartets at important locations, as KEK units were formed at Vaux, Avillers, Jametz and Cunel, and other places along the Western Front to as Luftwachtdienst (aerial guard force) units, consisting only of fighters. By April 1916, the air superiority established by the Eindecker pilots in the Fokker Scourge and maintained by their use within the KEK formations had long gone when the Halberstadt D.II the first German biplane fighter design, began to reach the front with the first Fokker D-series biplane fighters joining the Halberstadts. A target was set to establish 37 new squadrons in the next 12 months, equipped with single-seat fighters, manned by specially selected and trained pilots, to counter the Allied fighter squadrons already experiencing considerable success, as operated by the Royal Flying Corps and the French Aéronautique Militaire.
Boelcke, as the leading fighter pilot of the day, was called on to organise the manning, equipment and training, of the prototype for these new squadrons Jasta 2, the second of seven Jagdstaffeln to be established (on paper). Initially Jasta 2 was equipped with a motley of fighters, including early Fokker and Halberstadt "D" types. In September Jasta 2 began to receive the first of the superior Albatros fighters, that would enable the German fighter squadrons to re-gain a measure of air superiority in the following year. Boelcke was killed in an air collision on October 28 but his tactics, especially formation flying and a combination of aggression and prudence known as the Dicta Boelcke, remained the core of Jagdstaffel practice in the Luftstreitkräfte's fighter arm for the rest of the war. Several of the pilots of Jasta 2, trained by Boelcke, became fighter leaders, notably Manfred von Richthofen.
By April 1917, the 37 Jastas projected a year before were in service and had established air superiority on the Western Front, April 1917 (known ever since as Bloody April) is still regarded as the most disastrous period in the history of British military aviation. This ascendency was not to last, as new allied fighters (most famously, the S.E.5a, the Sopwith Camel and the SPAD S.XIII) were already starting to come into service, all of which more than matched the last of the Albatros fighters to see squadron service, the disappointing D.V/D.Va.
The Jagdstaffeln had concentrated on hindering the work of the Allied two-seater corps, reconnaissance and bombing squadrons. Offensive incursions by fighters any distance behind Allied lines were avoided, risking attrition that Germany could not withstand. 
Publicity for successful pilots of the Jagdstaffeln and the cult of the Air ace rapidly established their status as elite units and the various squadrons became associated with the different kingdoms of the German Empire. Most Jastas (eventually about 67 of them) were considered to be Prussian and other Jastas were associated with the kingdoms of Bavaria, Saxony and Württemberg. The Bavarian units in particular were associated for organisational and supply purposes with the (theoretically independent) Bavarian army, which did not add to overall efficiency in these departments. 
To obtain a local and temporary air superiority, larger fighter units were established, composed of several Jastas, Jagdgeschwader and Jagdgruppen. These units were moved from one section of the front to another, as the tactical situation demanded. The most famous of these units was Jagdgeschwader 1 - composed of Jastas 4, 6, 10 and 11, commanded by Richthofen until he was killed, many of whom flew the supremely manoeuvrable Fokker Dr.I triplane from the autumn of 1917. By March 1918 there were 80 Jagdstaffeln in the Luftstreitkräfte, most of them equipped with Albatros D.Vs. Then a long overdue re-equipment with new types, most notably the Fokker D.VII began, which for the first time since mid-1917, gave the Jastas equipment that matched their opponents'.
Personal colour schemes
German aircraft left the factory in a standard finish - although this differed from one manufacturer to another. Initial clear varnish on fabric and wooden surfaces had changed by 1916 to various camouflage schemes. In the Jagdstaffeln this gave way to a riot of colour, as pilots repainted their machines as they pleased. In January 1917, when he took over Jasta 11, Richthofen celebrated by painting his Albatros red and the squadron followed suit, painting at least part of their machines red, while Richthofen had the only all-red machine.
Other Jastas soon adopted the fashion until few fighters flew in the manufacturers' finish, their fuselages in particular at least sporting the pilot's monogram or perhaps his favourite colour(s), even if the wings remained in camouflage. A squadron theme was sometimes followed, with machines decorated in similar colours or with similar motifs but generally personal preference seems to have been standard. More than one pilot (on both sides) recorded that the contrast with the plain khaki of RFC fighters was helpful to all involved in rapidly distinguishing friend from foe in the hurly-burly of a dogfight and might have aided the accreditation of air victories claimed by individual German pilots.
- Gray & Thetford, p.ix
- Cheesman, p.12
- Guttman, Jon (Summer 2009). "Verdun: The First Air Battle for the Fighter: Part I - Prelude and Opening" (PDF). Relevance (The Great War Society) 18 (3): 9. Retrieved May 26, 2014.
- Gray & Thetford, pp xxviii–xxix
- Gray & Thetford, p.xxx
- Shores, p. 14
- Other types of Luftstreitkräfte unit were used offensively but units undertaking strategic bombing, long range reconnaissance and ground support of German ground units, especially during offensives, were expected to operate without escort by fighter squadrons.
- Shacklady & Treadwell, 2002, p.97
- Gray & Thetford, p.xxx
- Robertson pp.61–62
- Cheesman, E.F., ed. (1962). Reconnaissance & Bomber Aircraft of the 1914–1918 War. Letchworth, UK: Harleyford.
- Franks, Norman (1998). Jasta War Chronology: A Complete Listing of Claims and Losses, August 1916–November 1918. London, UK: Grub Street. ISBN 1-898697-84-1.
- Gray, Peter & Thetford, Owen (1970) . German Aircraft of the First World War. London, UK: Putnam.
- Robertson, Bruce (1957). Aircraft Camouflage and Markings 1907–1954. Letchworth, UK: Harleyford.
- Shacklady, Edward & Treadwell, Terry C. (2002). Classic WWI Aircraft Profiles. London, UK: Cerberus. ISBN 1-84145-102-9.
- Franks, Norman; Bailey, Frank W. & Guest, Russell F. (1991). Above The Lines: The Aces and Fighter Units of the German Air Service, Naval Air Service, and Flanders Marine Corps, 1914–1918. London, UK: Grub Street. ISBN 0-948817-19-4.
- "Jagdstaffeln (Jastas)". The Aerodrome. 2015.