Joe McMillan was kind enough to send me a copy of AR 260-10 (U.S. Army flags regulation) dated 25 October 1944. Using the information contained therein, I have produced a set of GIF's depicting the flags and colors of the U.S. Army Air Corps and U.S. Army Air Forces of the WW II era.
Background: The Army Air Corps was the U.S. Army's aviation branch, to which belonged all flying units and all support units, such as aviation maintenance squadrons, which were aviation-oriented. Its branch badge was the winged propeller. The Army Air Forces consisted of the Army Air Corps plus units from other branches, e.g. Military Police, Coast Artillery (antiaircraft units), Transportation, Quartermaster, etc., that were necessary to support the tactical employment of air units. Thus, for example, the Eighth Air Force included a variety of non-Army Air Corps units. The Army Air Corps was a branch of service; the Army Air Forces was the combat organization.
AAC/AAF Flags: The branch colors of the Army Air Corps were ultramarine blue and golden orange, and these colors were featured on all AAC/AAF flags.
Tom Gregg, 29 April 2000