 Walker returned to the United States in January 1941 and joined the Air War Plans Division in the Office of the Chief of the United States Army Air Corps in Washington , D.C. , as an assistant chief of staff . Brigadier General Carl Andrew Spaatz was head of the division . Lieutenant Colonels Olds and Muir S. Fairchild , old colleagues of Walker 's from the Air Corps Tactical School , were two of Spaatz ' assistants . Walker was promoted to temporary lieutenant colonel on 15 July 1941 . In the June 1941 reorganization of the Air Corps , Spaatz became chief of staff to the Commanding General , United States Army Air Forces , Major General Henry H. Arnold , who appointed Colonel Harold L. George , a former student of Walker at the Air Corps Tactical School from 1931 to 1932 , to replace Spaatz as head of the Air War Plans Division . Walker joined George 's planning team , along with Majors Haywood S. Hansell and Laurence S. Kuter . All were former instructors at the Air Corps Tactical School and members of the " Bomber Mafia " . 
