Before April 1916, the German 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 actual "dedicated" fighter units until after the close of 1915.
The first step towards specialist fighter-only aviation units within the German military was the establishment of the so-called Kampfeinsitzer Kommando (single-seat battle unit, abbreviated as "KEK") 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 their former FFA units during the winter of 1915-16 and brought together in pairs and quartets at particularly strategic locations, as "KEK" units were formed at Vaux, Avillers, Jametz, and Cunel, as well as other strategic locations along the Western Front to act as Luftwachtdienst (aerial guard force) units, consisting only of fighters. By April 1916, the air superiority established by the Eindecker pilots and maintained by their use within the KEK formations had long evaporated as the Halberstadt D.II began to be phased in as Germany's first biplane fighter design, with the first Fokker D-series biplane fighters joining the Halberstadts, and a target was set to establish 37 new squadrons in the next 12 months - entirely equipped with single seat fighters, and 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. This was Jasta 2 - the second of the first seven Jagdstaffeln to be established (on paper). Initially Jasta 2 was equipped with a motley collection of fighters, including the various 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-establish German air superiority in the following year. Boelcke himself was killed in an air collision on October 28 - but his tactics, especially formation flying and a combination of aggressiveness and prudence known as the Dicta Boelcke, remained the core of Jagdstaffel practice throughout the Luftstreitkräfte's fighter arm for the rest of the war. Several of the pilots of Jasta 2, trained by Boelcke, became noted fighter leaders in their own right - most notably, of course, Manfred von Richthofen.
By April 1917 the 37 Jastas projected a year before were in service, and had established German air superiority on the Western Front - in fact 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.
By this time, if not earlier, employment of the Jagdstaffeln had become concentrated on the task of hindering the work of the Allied two-seater Corps, reconnaissance and bombing squadrons over the front itself, and German held territory. Offensive incursions by fighters any distance behind Allied lines were generally avoided, as risking a war of attrition that Germany was unlikely to win. 
Publicity surrounding the successful pilots of the jagdstaffeln 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 specifically Prussian; however other Jastas were associated with the kingdoms of Bavaria, Saxony, and Wuerttemberg. 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. 
In order to obtain a local and temporary air superiority larger fighter units were established, composed of several Jastas - and called 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, and commanded until his death by Richthofen, many of whose pilots could be seen flying the supremely maneuverable Fokker Dr.I triplane from the autumn of 1917 onwards.
By March 1918 there were 80 Jagdstaffeln in the Luftstreitkräfte - most of them still entirely or partially equipped with Albatros D.Vs. Shortly after this, 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 both fabric and wooden surfaces had changed by 1916 to various camouflage schemes. In the Jagdstaffeln, however, this gave way to a riot of colour, as individual pilots took to repainting their machines to their own personal preferences.
In January 1917, when he took over Jasta 11 as its new commander, Richthofen celebrated by painting his Albatros red. His squadron followed suit - all painting at least part of their machines red - while reserving to their commander the distinction of an all-red machine.
Other Jastas soon adopted the same fashion - until few German fighters flew entirely in the original manufacturers' finish - their fuselages in particular at least sporting their pilots' personal monogram, or perhaps his favourite colour(s) - even if the wings remained in camouflage. A squadron theme was sometimes followed, with all or most machines decorated in similar colours, or with similar motifs - but generally personal fancy seems to have been the order of the day.
More than one pilot (on both sides) recorded that the resulting contrast with the plain khaki brown of the RFC fighters was helpful to all involved in rapidly distinguishing friend from foe in the hurly burly of a dogfight. It also may well have visually aided the accreditation of air victories claimed by individual German fighter 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). http://www.worldwar1.com. The Great War Society. p. 9. Retrieved May 26, 2014.
- Gray & Thetford, pp xxviii-xxix
- Gray & Thetford, p.xxx
- Shores, p. 14
- Other types of Luftstreitkräfte unit were used much more 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 dedicated fighter squadrons.
- Shacklady & Treadwell, 2002, p.97
- Gray & Thetford, p.xxx
- Robertson pp.61-62
- Cheesman, E.F. (ed.) Reconnaissance & Bomber Aircraft of the 1914-1918 War. Letchworth, UK: Harleyford, 1962.
- Franks, Norman: Jasta War Chronology: A Complete Listing of Claims and Losses, August 1916-November 1918 - 1998 - ISBN= 1-898697-84-1
- Gray, Peter & Thetford, Owen: German Aircraft of the First World War - London, Putman, 1962/1970
- Robertson, Bruce: Aircraft Camouflage and Markings 1907-1954. Letchworth, UK: Harleyford, 1957.
- Shacklady, Edward & Terry C. Treadwell:Classic WWI Aircraft Profiles - London: Cerberus, 2002 - ISBN 1-84145-102-9
- Shores, Norman, L.R. Franks and Russell Guest. Above the Trenches: A Complete Record of the Fighter Aces and the Units of the British Empire Air Forces 1915 -1920. London: Grub Street, 1991. ISBN 0-948817-19-4.