Jagdgeschwader I of World War I, was a fighter wing of the German Luftstreitkräfte, comprising four Jastas. The first unit of its type formed under that classification, JG I was formed on 24 June 1917, with Manfred von Richthofen as commanding officer, by combining Jastas 4, 6, 10 and 11. JG I became known as "The Flying Circus" or "Richthofen's Circus" because of the bright colours of its aircraft, and perhaps also because of the way the unit was transferred from one area of Allied air activity to another – moving like a travelling circus in trains, and frequently setting up in tents on improvised airfields.

The Deutsche Luftstreitkräfte —known before October 1916 as Die Fliegertruppen des deutschen Kaiserreiches —was the air arm of the Imperial German Army. In English-language sources it is usually referred to as the Imperial German Air Service, although that is not a literal translation of either name. German naval aviators of the Marine-Fliegerabteilung were an integral part of the Imperial German Navy. Both military branches operated aeroplanes, observation balloons and airships.