April 20 - the Escadrille Américanne, later to be known as Lafayette Escadrille, is established as an American volunteer unit in France, equipped with Nieuport 11s.
May
May 2 - eight German Zeppelins raid the east coast of England, causing 39 casualties. The Zeppelin L 20 (LZ59) is wrecked in a storm off Stavanger, Norway on the return journey.
July 1 - beginning of the Battle of the Somme. In the five months of the battle, the British lose 782 aircraft and 576 pilots but maintain air superiority over the battlefield.
September 15 - British submarine B-10 is sunk by AustrianLohnerflying boats, led by Fregatten-Leutnant Zelezny, becoming the first submarine sunk by aircraft; French submarine Foucault is sunk by two Austrian Lohner flying boats, led by Fregatten-Leutnant Zelezny, becoming the first submarine sunk at sea by aircraft.