The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and de facto aerial warfare service branch of the United States during and immediately after World War II (1941–1947). It was created on 20 June 1941 as successor to the previous United States Army Air Corps and is the direct predecessor of the United States Air Force, today one of the six armed forces of the United States. The AAF was a component of the United States Army, which on 2 March 1942 was divided functionally by executive order into three autonomous forces: the Army Ground Forces, the United States Army 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.

The AAF administered all parts of military aviation formerly distributed among the Air Corps, General Headquarters Air Force, and the ground forces' corps area commanders and thus became the first air organization of the U.S. Army to control its own installations and support personnel. The peak size of the AAF during World War II was over 2.4 million men and women in service and nearly 80,000 aircraft by 1944, and 783 domestic bases in December 1943.Nalty (1997), pp. 176 and 378. Also, see growth tables above. By "V-E Day", the Army Air Forces had 1.25 million men stationed overseas and operated from more than 1,600 airfields worldwide.AAF Statistical Digest, Table 215 – Airfields in CONUS 1941–1945; Table 217 – Airfields outside CONUS 1941–1945.

The Army Air Forces was created in June 1941 to provide the air arm greater autonomy in which to expand more efficiently, to provide a structure for the additional command echelons required by a vastly increased force, and to end an increasingly divisive administrative battle within the Army over control of aviation doctrine and organization that had been ongoing since the creation of an aviation section within the U.S. Army Signal Corps in 1914. The AAF succeeded both the Air Corps, which had been the statutory military aviation branch since 1926 and the GHQ Air Force, which had been activated in 1935 to quiet the demands of airmen for an independent Air Force similar to the Royal Air Force which had already been established in the United Kingdom.

Although other nations already had separate air forces independent of their army or navy (such as the Royal Air Force and the German Luftwaffe), the AAF remained a part of the Army until a defense reorganization in the post-war period resulted in the passage by the United States Congress of the National Security Act of 1947 with the creation of an independent United States Air Force in September 1947.

In its expansion and conduct of the war, the AAF became more than just an arm of the greater organization. By the end of World War II, the Army Air Forces had become virtually an independent service. By regulation and executive order, it was a subordinate agency of the United States Department of War (as were the Army Ground Forces and the Army Service Forces) tasked only with organizing, training, and equipping combat units and limited in responsibility to the continental United States. In reality, Headquarters AAF controlled the conduct of all aspects of the air war in every part of the world, determining air policy and issuing orders without transmitting them through the Army Chief of Staff. This "contrast between theory and fact is...fundamental to an understanding of the AAF."Craven and Cate, Vol. 6, pp. 28–29

Creation Unity of command problems in the Air Corps The basis of the Army Air Forces arose in the formulation of theories of strategic bombing at the Air Corps Tactical School that gave new impetus to arguments for an independent air force, beginning with those espoused by Brig. Gen. Billy Mitchell that led to his later court-martial. Despite a perception of resistance and even obstruction then by the bureaucracy in the War Department General Staff (WDGS), much of which was attributable to lack of funds, the Air Corps later made great strides in the 1930s, both organizationally and in doctrine. A strategy stressing precision bombing of industrial targets by heavily armed, long-range bombers emerged, formulated by the men who would become its leaders.Nalty (1997), pp. 112–113.

A major step toward a separate air force came in March 1935, when the command of all combat air units within the Continental United States (CONUS) was centralized under a single organization called the "General Headquarters Air Force". Since 1920, control of aviation units had resided with commanders of the corps areas (a peacetime ground forces administrative echelon), following the model established by commanding General John J. Pershing during World War I. In 1924, the General Staff planned for a wartime activation of an Army general headquarters (GHQ), similar to the American Expeditionary Forces model of World War I, with a GHQ Air Force as a subordinate component. Both were created in 1933 when a small conflict with Cuba seemed possible following a coup d'état but was not activated.

The activation of GHQ Air Force represented a compromise between strategic airpower advocates and ground force commanders who demanded that the Air Corps mission remain tied to that of the land forces. Airpower advocates achieved a centralized control of air units under an air commander, while the WDGS divided authority within the air arm and assured a continuing policy of support of ground operations as its primary role.Nalty (1997), p. 130. GHQ Air Force organized combat groups administratively into a strike force of three wings deployed to the Atlantic, Pacific, and Gulf coasts but was small in comparison to European air forces. Lines of authority were difficult, at best, since GHQ Air Force controlled only operations of its combat units while the Air Corps was still responsible for doctrine, acquisition of aircraft, and training. Corps area commanders continued to exercise control over airfields and administration of personnel, and in the overseas departments, operational control of units as well.Three examples of the negative effects of this long-ingrained policy, even after creation of the AAF, occurred in Hawaii in the six months preceding the Japanese attack on Pearl Harbor, where neither the Air Corps nor the AFCC had any command jurisdiction. First, Maj. Gen. Walter C. Short, commanding general of the U.S. Army's Hawaiian Department, held the opinion that the Hawaiian Air Force was grossly overstaffed and mandated in July 1941 that its non-flying AAF personnel complete infantry training, a program that took them from their primary jobs for a period of six to eight weeks. Second, efforts in October and November to complete gunnery training for B-17 gunners were stifled when aircrew were used by the Hawaiian Department to guard warehouses in Honolulu. Finally, after the War Department issued a war warning to Pacific commands on 27 November, Short insisted despite objections from his air commanders that aircraft be parked close together on open ramps as a security measure against sabotage rather than being dispersed in revetments for protection against air attack. (Arakaki and Kuborn, pp. 5–6, 38) Between March 1935 and September 1938, the commanders of GHQ Air Force and the Air Corps, Major Generals Frank M. Andrews and Oscar Westover respectively, clashed philosophically over the direction in which the air arm was moving, exacerbating the difficulties.Nalty (1997), pp. 131–133.

The expected activation of Army General Headquarters prompted Army Chief of Staff George C. Marshall to request a reorganization study from Chief of the Air Corps Maj. Gen. Henry H. Arnold resulting on 5 October 1940 in a proposal for creation of an air staff, unification of the air arm under one commander, and equality with the ground and supply forces. Arnold's proposal was immediately opposed by the General Staff in all respects, rehashing its traditional doctrinal argument that, in the event of war, the Air Corps would have no mission independent of support of the ground forces. Marshall implemented a compromise that the Air Corps found entirely inadequate, naming Arnold as acting "Deputy Chief of Staff for Air" but rejecting all organizational points of his proposal. GHQ Air Force instead was assigned to the control of Army General Headquarters, although the latter was a training and not an operational component, when it was activated in November 1940. A division of the GHQ Air Force into four geographical air defense districts on 19 October 1940 was concurrent with the creation of air forces to defend Hawaii and the Panama Canal. The air districts were converted in March 1941 into numbered air forces with a subordinate organization of 54 groups.Craven and Cate, Vol. 6, pp. 17–18.

Army Air Forces created

The likelihood of U.S. participation in World War II prompted the most radical reorganization of the aviation branch in its history, developing a structure that both unified command of all air elements and gave it total autonomy and equality with the ground forces by March 1942.

In the spring of 1941, the success in Europe of air operations conducted under centralized control (as exemplified by the British Royal Air Force and the German Wehrmacht's military air arm, the Luftwaffe) made clear that the splintering of authority in the American air forces, characterized as "hydra-headed" by one congressman,Rep. James G. Scrugham (D-Nev). (Craven and Cate Vol. 6, p. 24) had caused a disturbing lack of clear channels of command. Less than five months after the rejection of Arnold's reorganization proposal, a joint U.S.-British strategic planning agreement (ABC-1) refuted the General Staff's argument that the Air Corps had no wartime mission except to support ground forces.Craven and Cate, Vol. 6, p. 20 A struggle with the General Staff over control of air defense of the United States had been won by airmen and vested in four command units called "numbered air forces", but the bureaucratic conflict threatened to renew the dormant struggle for an independent United States Air Force. Marshall had come to the view that the air forces needed a "simpler system" and a unified command. Working with Arnold and Robert A. Lovett, recently appointed to the long-vacant position of Assistant Secretary of War for Air, he reached a consensus that quasi-autonomy for the air forces was preferable to immediate separation.