Jasta is a
contraction of
Jagdstaffel, a
German compound word of
Jagd ("hunting") and
staffel ("squadron").
During World War I, air superiority seesawed back and forth a few times. Initially, early in the war, the German forces achieved great success with the Fokker Eindecker (Fokker Monoplane). The RAF immediately began to iterate its aircraft in an attempt to compete, and by early 1916 had done so - British air forces generally held sway over the Western Front. The Battle of the Somme, irrespective of the outcome on the ground, was particularly disastrous for the German air forces. As a consequence, Germany reorganized its flying corps. These were given greater separation from the ground forces, and renamed Deutsche Luftstreitkräfte (German Air Forces). One of the first tasks of this new organization was to determine how to regain air superiority.
One of the consequence of the earlier Imperial German Army Air Service being (as its name describes) an adjunct of the ground forces was that its units were organized for the maximum benefit of those ground forces. Units of the Army Air Service contained a mix of aircraft types so as to be able to perform various tasks as required - reconnaissance, bombing, escort of those others, and so on.
The largest change upon the reorganization was a plan to deploy a large number of units composed entirely of single-seat fighters, whose mission would be to achieve air superiority in their areas of operations rather than to perform jobbing tasks for associated ground units. These units, the first dedicated fighter squadrons in German service, were named Jagdstaffel - and a year after this decision was made (in other words, by around April of 1917) the first Jastas were flying.
The Jasta unit was a noteworthy success. German fliers began to significantly outscore their British and French opponents. Eventually, the Jastas were further aggregated into Jagdgeschwaders - the famous 'flying circuses' of British parlance.
By World War II the Fighter Squadron and Fighter Wing were established concepts and in use by all combatants.
Iron Noder 2010