Army One is the call sign of any United States Army aircraft carrying the President of the United States. From 1957 until 1976, this was usually an Army helicopter transporting the President. Responsibilty for helicopter transportation of the President was divided between the Army and the U.S. Marine Corps, prior to 1976, when the Marine Corps was given the sole responsiblity of transporting the President by helicopter.

The most famous duty for Army One was on August 9, 1974, when President Richard Nixon delivered his famous "V" sign after resigning his office in the wake of the Watergate scandal.