United States Air Force
The U.S. War Department created the first antecedent of the U.S. Air Force, as a part of the U.S. Army, on 1 August 1907, which through a succession of changes of organization, titles, and missions advanced toward eventual independence 40 years later. In World War II, almost 68,000 U.S. airmen died helping to win the war, with only the infantry suffering more casualties. In practice, the U.S. Army Air Forces (USAAF) was virtually independent of the Army during World War II, and in virtually all ways functioned as an independent service branch, but airmen still pressed for formal independence. The National Security Act of 1947 was signed on 26 July 1947 by President Harry S Truman, which established the Department of the Air Force, but it was not until 18 September 1947, when the first secretary of the Air Force, W. Stuart Symington, was sworn into office that the Air Force was officially formed as an independent service branch.
Military Air Transport Service
When the United States Air Force was established as a separate service in 1947, the Air Transport Command was not established as one of its major commands. The ATC commander and his staff took it upon themselves to convince the new civilian leadership of the newly created Department of Defense (DOD) (and Secretaries of the Army and Air Force) that ATC had a mission. They seized upon testimony by former I Troop Carrier Command commander Major General Paul L. Williams that the Air Force should have a long-range troop deployment capability, and began advocating that ATC transports could be used to deploy troops. Williams had been pressing for the development of a long-range troop carrier airplane when he made his statement.