On December 9, 1942, the U.S. Army was reorganized into three autonomous forces: Army Air Forces, Ground Forces and Services of Supply.
The Department of the Air Force, an agency of the Department of Defense, was established on September 18, 1947, pursuant to provisions of the National Security Act of the previous July 26. On September 26, 1947, by order of the Secretary of Defense, personnel of the Army Air Forces (AAF) were transferred from the Department of the Army (formerly the War Department) to the Department of the Air Force and established as the United States Air Force (USAF).
