Henry Harley "Hap" Arnold was an American general officer holding the ranks of General of the Army and later, General of the Air Force. Arnold was an aviation pioneer, Chief of the Air Corps (1938–1941), commanding general of the United States Army Air Forces, the only United States Air Force general to hold five-star rank, and the only officer to hold a five-star rank in two different U.S. military services. Arnold was also the founder of Project RAND, which evolved into one of the world's largest non-profit global policy think tanks, the RAND Corporation, and was one of the founders of Pan American World Airways.

The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical rift developed between more traditional ground-based army personnel and those who felt that aircraft were being underutilized and that air operations were being stifled for political reasons unrelated to their effectiveness. The USAAC was renamed from the earlier United States Army Air Service on 2 July 1926, and was part of the larger United States Army. The Air Corps became the United States Army Air Forces (USAAF) on 20 June 1941, giving it greater autonomy from the Army's middle-level command structure. During World War II, although not an administrative echelon, the Air Corps (AC) remained as one of the combat arms of the Army until 1947, when it was legally abolished by legislation establishing the Department of the Air Force.