German Leutnant Kurt Wintgens, flying the Fokker M.5K/MG, E.5/15 production prototype of the Fokker Eindecker fighter (one of five built) armed with a Parabellum MG14 gun, achieves the first claimed aerial victory using a synchronization gear which allows a machine gun to shoot through a turning propeller without hitting its blades. He claimed downing a Morane-Saulnier L two-seat “parasol” observation aircraft over the Western Front. However, the claim is unconfirmed because the aircraft fell beyond German lines. Wintgens would down two more Morane Type L two-seaters, one each on July 4 (again unconfirmed) and 15, with the July 15th victory being his first confirmed victory, all achieved with E.5/15.

Wintgens battle begins the “Fokker scourge,” the first period of German air superiority, in which German Fokker Eindeckers will take a heavy toll of Allied aircraft over the Western Front.

The French Navy seaplane carrier Pas-de-Calais is commissioned. She is the first paddle steamer to serve as an aviation vessel.

The US Department of the Navy establishes an Office of Naval Aeronautics, the first formal recognition of naval aviation within the United States Navy bureaucracy.