<Li> U.S. Army Air Corps (2 July 1926--20 June 1941) * </Li> <Li> U.S. Army Air Forces (20 June 1941--17 September 1947) * * </Li> <P> * The Air Corps became a subordinate element of the Army Air Forces on 20 June 1941, and was abolished as an administrative organization on 9 March 1942 . It continued to exist as a branch of the Army (similar to the infantry, quartermaster, or artillery) until reorganization provisions of the National Security Act of 1947 (61 Stat. 495), 26 July 1947 . </P> <P> * * The Army Air Forces were abolished by Transfer Order 1, Office of the Secretary of Defense, 26 September 1947, implementing the same provisions . Transfer Order 1 was the first of 200 Army - Air Force transfer agreements drawn up in June and July 1947, and ordered the transfer of all military and civilian personnel of the Army Air Forces to the Department of the Air Force and the USAF . The final transfer order was signed 22 June 1949 . </P>

When did the army air corps become the us air force