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.
Aviation Section, U.S. Signal Corps
The Aviation Section, Signal Corps was created by the 63rd Congress (Public Law 143) on 18 July 1914 after earlier legislation to make the aviation service independent from the Signal Corps died in committee. From July 1914 until May 1918 the aviation section of the Signal Corps was familiarly known by the title of its administrative headquarters component at the time, seen variously as the Aeronautical Division, Air Division, Division of Military Aeronautics, and others. For historic convenience, however, the air arm is most commonly referred to by its official designation, the Aviation Section, Signal Corps (ASSC), and is the designation recognized by the United States Air Force as its predecessor for this period.