The United States Army Air Forces (USAAF or AAF) was the military aviation service of the United States of America during and immediately after World War II, successor to the United States Army Air Corps and the direct predecessor of the United States Air Force. The AAF were a component of the United States Army, which in 1942 was divided functionally by executive order into three autonomous forces: the Army Ground Forces, the Services of Supply (which in 1943 became the Army Service Forces), and the Army Air Forces. Each of these forces had a commanding general who reported directly to the Army Chief of Staff.