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.
Henry H. Arnold
The division of authority between the Air Corps and the GHQ Air Force was removed with promulgation of Army Regulation 95–5, creating the United States Army Air Forces on June 20, 1941, only two days before Germany's invasion of the Soviet Union. Arnold became Chief of the Army Air Forces and acting "Deputy Chief of Staff for Air" with authority over both the Air Corps and Air Force Combat Command (successor to GHQAF). While this provided the air arm with a staff of its own and brought the entire organization under the command of one general, it failed to grant the degree of autonomy sought. By consensus between Marshall and Arnold, debate on separation of the Air Force into a service co-equal with the Army and Navy was postponed until after the war.