The Air Medal is a military decoration of the United States Armed Forces created in 1942 by Executive Order 9158, signed by Franklin D. Roosevelt. It is awarded for single acts of heroism or meritorious achievement while participating in aerial flight.
The original award criteria set by an Army Policy Letter dated September 25, 1942 was for one award of the Air Medal:
per each naval vessel or three enemy aircraft in flight confirmed destroyed. An entire aircrew would be credited for the destruction of a ship, but only the pilot or gunner responsible would be credited for destroying an enemy aircraft.
per 25 operational flights during which exposure to enemy fire is expected.
per 100 operational flights during which exposure to enemy fire is not expected.