United States Army Air Corps
Branch insignia of the Army Air Corps
Active	1926 – 1942
Disbanded	September 18, 1947
Country	United States
Branch	Army
Type	Air force
Role	Aerial warfare
Size	14,650 men, 1,646 aircraft (1932) 16,863 men, 855 aircraft (1936) 152,125 men, 6,777 aircraft (1941)
Garrison/HQ	Munitions Building, Washington, D.C.
Colors	Ultramarine blue and golden orange
March	Army Air Corps
Engagements	World War II
Commanders
Notable commanders	Major General Benjamin D. Foulois Major General Henry H. Arnold
Insignia
Roundel

The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical rift developed between more traditional ground-based army personnel and those who felt that aircraft were being underutilized and that air operations were being stifled for political reasons unrelated to their effectiveness. The USAAC was renamed from the earlier United States Army Air Service on 2 July 1926, and was part of the larger United States Army. The Air Corps became the United States Army Air Forces (USAAF) on 20 June 1941, giving it greater autonomy from the Army's middle-level command structure. During World War II, although not an administrative echelon, the Air Corps (AC) remained as one of the combat arms of the Army until 1947, when it was legally abolished by legislation establishing the Department of the Air Force.^[1]

The Air Corps was renamed by the United States Congress largely as a compromise between the advocates of a separate air arm and those of the traditionalist Army high command who viewed the aviation arm as an auxiliary branch to support the ground forces. Although its members worked to promote the concept of air power and an autonomous air force in the years between the world wars, its primary purpose by Army policy remained support of ground forces rather than independent operations.

On 1 March 1935, still struggling with the issue of a separate air arm, the Army activated the General Headquarters Air Force for centralized control of aviation combat units within the continental United States, separate from but coordinate with the Air Corps. The separation of the Air Corps from control of its combat units caused problems of unity of command that became more acute as the Air Corps enlarged in preparation for World War II. This was resolved by the creation of the Army Air Forces (AAF), making both organizations subordinate to the new higher echelon.

On 20 June 1941, the Army Air Corps' existence as the primary air arm of the U.S. Army changed to that of solely being the training and logistics elements of the then-new United States Army Air Forces, which embraced the formerly-named General Headquarters Air Force under the new Air Force Combat Command organization for front-line combat operations; this new element, along with the Air Corps, comprised the USAAF.^[2]

The Air Corps ceased to have an administrative structure after 9 March 1942, but as "the permanent statutory organization of the air arm, and the principal component of the Army Air Forces," the overwhelming majority of personnel assigned to the AAF were members of the Air Corps.^[3]

Creation of the Air Corps[edit]

The U.S. Army Air Service had a brief but turbulent history. Created during World War I by executive order of President Woodrow Wilson after America entered the war in April 1917 as the increasing use of airplanes and the military uses of aviation were readily apparent as the war continued to its climax, the U.S. Army Air Service gained permanent legislative authority in 1920 as a combatant arm of the line of the United States Army. There followed a six-year struggle between adherents of airpower and the supporters of the traditional military services about the value of an independent Air Force, intensified by struggles for funds caused by skimpy budgets, as much an impetus for independence as any other factor.^[5]

The Lassiter Board, a group of General Staff officers, recommended in 1923 that the Air Service be augmented by an offensive force of bombardment and pursuit units under the command of Army general headquarters in time of war, and many of its recommendations became Army regulations. The War Department desired to implement the Lassiter Board's recommendations, but the administration of President Calvin Coolidge chose instead to economize by radically cutting military budgets, particularly the Army's.^{[6][n 1]} The Lampert Committee of the House of Representatives in December 1925 proposed a unified air force independent of the Army and Navy, plus a department of defense to coordinate the three armed services.^[7] However another board, headed by Dwight Morrow, was appointed in September 1925 by Coolidge ostensibly to study the "best means of developing and applying aircraft in national defense" but in reality to minimize the political impact of the pending court-martial of Billy Mitchell (and to preempt the findings of the Lampert Committee). It declared that no threat of air attack was likely to exist to the United States, rejected the idea of a department of defense and a separate department of air, and recommended minor reforms that included renaming the air service to allow it "more prestige."^[8]

In early 1926 the Military Affairs Committee of the Congress rejected all bills set forth before it on both sides of the issue. They fashioned a compromise in which the findings of the Morrow Board were enacted as law, while providing the air arm a "five-year plan" for expansion and development. Maj. Gen. Mason Patrick, the Chief of Air Service, had proposed that it be made a semi-independent service within the War Department along the lines of the Marine Corps within the Navy Department, but this was rejected; only the cosmetic name change was accepted.^{[9][n 2]} The legislation changed the name of the Air Service to the Air Corps, (in the words of one analyst) "thereby strengthening the conception of military aviation as an offensive, striking arm rather than an auxiliary service."^[10]

The Air Corps Act (44 Stat. 780) became law on 2 July 1926. In accordance with the Morrow Board's recommendations, the act created an additional Assistant Secretary of War to "help foster military aeronautics", and established an air section in each division of the General Staff for a period of three years. Two additional brigadier generals would serve as assistant chiefs of the Air Corps.^{[11][n 3]} Previous provisions of the National Defense Act of 1920 that all flying units be commanded only by rated personnel and that flight pay be awarded were continued. The Air Corps also retained the "Prop and Wings" as its branch insignia through its disestablishment in 1947. Patrick became Chief of the Air Corps and Brig. Gen. James E. Fechet continued as his first assistant chief. On 17 July 1926, two lieutenant colonels were promoted to brigadier general for four-year terms as assistant chiefs of Air Corps: Frank P. Lahm, to command the new Air Corps Training Center, and William E. Gillmore, in command of the Materiel Division.^{[12][n 4]}

Of the new law and organization, however, Wesley F. Craven and James L. Cate in the official history of the United States Army Air Forces concluded that:

"The bill which was finally enacted purported to be a compromise, but it leaned heavily on the Morrow recommendations. The Air Corps Act of 2 July 1926 effected no fundamental innovation. The change in designation meant no change in status: the Air Corps was still a combatant branch of the Army with less prestige than the Infantry."^[11]

The position of the air arm within the Department of War remained essentially the same as before, that is, the flying units were under the operational control of the various ground forces corps area commands and not the Air Corps, which remained responsible for procurement and maintenance of aircraft, supply, and training. Because of a lack of legally specified duties and responsibilities, the new position of Assistant Secretary of War for Air, held by F. Trubee Davison from July 1926 to March 1933, proved of little help in promoting autonomy for the air arm.^[13]

Five-year expansion program[edit]

The Air Corps Act gave authorization to carry out a five-year expansion program. However, a lack of appropriations caused the beginning of the program to be delayed until 1 July 1927. Patrick proposed an increase to 63 tactical squadrons (from an existing 32) to maintain the program of the Lassiter Board already in effect, but Chief of Staff Gen. John Hines rejected the recommendation in favor of a plan drawn up by ground force Brig. Gen. Hugh Drum that proposed 52 squadrons.^{[14][15][n 5]} The act authorized expansion to 1,800 airplanes, 1,650 officers, and 15,000 enlisted men, to be reached in regular increments over a five-year period. None of the goals was reached by July 1932. Neither of the relatively modest increases in airplanes or officers was accomplished until 1938 because adequate funds were never appropriated and the coming of the Great Depression forced reductions in pay and modernization across the board in the Army.^[16] Organizationally the Air Corps doubled from seven to fifteen groups, but the expansion was meaningless because all were seriously understrength in aircraft and pilots.^[17] (Origin of first seven groups shown here)

As units of the Air Corps increased in number, so did higher command echelons. The 2nd Wing, activated in 1922 as part of the Air Service, remained the only wing organization in the new Air Corps until 1929, when it was redesignated the 2nd Bombardment Wing in anticipation of the activation of the 1st Bombardment Wing to provide a bombardment wing on each coast.^[18] The 1st Bomb Wing was activated in 1931, followed by the 3rd Attack Wing in 1932 to protect the Mexican border, at which time the 1st became the 1st Pursuit Wing. The three wings became the foundation of General Headquarters Air Force upon its activation in 1935.

Aircraft and personnel 1926–1935[edit]

The Air Corps adopted a new color scheme for painting its aircraft in 1927, heretofore painted olive drab. The wings and tails of aircraft were painted chrome yellow, with the words "U.S. ARMY" displayed in large black lettering on the undersurface of the lower wings. Tail rudders were painted with a vertical dark blue band at the rudder hinge and 13 alternating red-and-white horizontal stripes trailing. The painting of fuselages olive drab was changed to blue in the early 1930s, and this motif continued until late 1937, when all new aircraft (now all-metal) were left unpainted except for national markings.^[19]

Most pursuit fighters before 1935 were of the Curtiss P-1 Hawk (1926–1930) and Boeing P-12 (1929–1935) families, and before the 1934 introduction of the all-metal monoplane, most front-line bombers were canvas-and-wood variants of the radial engined Keystone LB-6 (60 LB-5A, LB-6 and LB-7 bombers) and B-3A (127 B-3A, B-4A, B-5, and B-6A bombers) designs.^{[n 6]} Between 1927 and 1934, the Curtiss O-1 Falcon was the most numerous of the 19 different types and series of observation craft and its A-3 variant the most numerous of the attack planes that fulfilled the observation/close support role designated by the General Staff as the primary mission of the Air Corps.^[20]

Transport aircraft used during the first ten years of the Air Corps were of largely trimotor design, such as the Atlantic-Fokker C-2 and the Ford C-3, and were procured in such small numbers (66 total) that they were doled out one airplane to a base. As their numbers and utility declined, they were replaced by a series of 50 twin-engine and single-engine small transports and used for staff duties. Pilot training was conducted between 1927 and 1937 in the Consolidated PT-3 trainer, followed by the Stearman PT-13 and variants after 1937.

By 1933 the Air Corps expanded to a tactical strength of 50 squadrons: 21 pursuit, 13 observation, 12 bombardment, and 4 attack. All were understrength in aircraft and men, particularly officers, which resulted in most being commanded by junior officers (commonly first lieutenants)^{[n 7]} instead of by majors as authorized.^[21] The last open-cockpit fighter used by the Air Corps, the Boeing P-26 Peashooter, came into service in 1933 and bridged the gap between the biplane and more modern fighters.

The Air Corps was called upon in early 1934 to deliver mail in the wake of the Air Mail scandal, involving the postmaster general and heads of the airlines. Despite an embarrassing performance that resulted from numerous crashes and 13 fatalities and was deemed a "fiasco" in the media, investigating boards in 1933–1934^{[n 8]} recommended organizational and modernization changes that again set the Air Corps on the path to autonomy and eventual separation from the Army. A force of 2,320 aircraft was recommended by the Drum Board,^{[n 9]} and authorized by Congress in June 1936, but appropriations to build up the force were denied by the administration until 1939, when the probability of war became apparent. Instead, the Air Corps inventory actually declined to 855 total aircraft in 1936, a year after the creation of GHQ Air Force, which by itself was recommended to have a strength of 980.^[22]

The most serious fallout from the Air Mail fiasco was the retirement under fire of Major General Benjamin Foulois as Chief of Air Corps. Soon after the Roosevelt administration placed the blame on him for the Air Corps' failures, he was investigated by a congressional subcommittee alleging corruption in aircraft procurement. The matter resulted in an impasse between committee chairman William N. Rogers and Secretary of War George Dern before being sent to the Army's Inspector General, who ruled largely in favor of Foulois. Rogers continued to severely criticize Foulois through the summer of 1935, threatening future Air Corps appropriations, and despite public support by Dern for the embattled chief, the administration was close to firing Foulois for his perceived attitude as a radical airman and his public criticisms of the administration during the controversy. He retired in December 1935 for the good of the service.^[23][24]

The Roosevelt administration began a search for his replacement in September 1935, narrowing the choice to two of the three assistant chiefs, Henry Conger Pratt and Oscar Westover. Pratt appeared to have the superior credentials, but he had been in charge of aircraft procurement during the Foulois years and was looked upon warily by Dern as possibly being another Mitchell or Foulois. Westover was chosen because he was the philosophical opposite of the two insurgent airmen in all respects, being a "team player".^[24]

The open insurgency between 1920 and 1935 of airmen foreseeing a need for an independent air force in order to develop fully the potential of airpower had cost the careers of two of its near-legendary lights, Foulois and Mitchell, and nearly cost the reputation of two others, Pratt and Henry H. Arnold. In terms of the principle of civilian control of the military in peacetime, their tactics and behavior were clearly inappropriate. The political struggle had temporarily alienated supporters in Congress, had been counterproductive of the development of the Air Corps in the short run, and had hardened the opposition of an already antagonistic General Staff. But through their mistakes and repeated rebuffs, the airmen had learned what they were lacking: proof for the argument that the Air Corps could perform a unique mission—strategic bombardment—and the real threat of another world war would soon reverse their fortunes.^[25]

Doctrinal development[edit]

Strategic bombardment in roles and missions[edit]

In March 1928, commenting on the lack of survivability in combat of his unit's Keystone LB-7 and Martin NBS-1 bombers, Lt. Col. Hugh J. Knerr, commander of the 2nd Bombardment Group at Langley Field, Virginia, recommended that the Air Corps adopt two types of all-metal monoplane bombers, a short-range day bomber and a long-range night bomber. Instructors at the Air Corps Tactical School (ACTS), also then at Langley, took the concept one step further in March 1930 by recommending that the types instead be light and heavy, the latter capable of long range carrying a heavy bomb load that could also be used during daylight.^[27]

The Air Corps in January 1931 "got its foot in the door" for developing a mission for which only it would have capability, while at the same time creating a need for technological advancement of its equipment. Chief of Naval Operations Admiral William V. Pratt wanted approval of his proposition that all naval aviation including land-based aircraft was by definition tied to carrier-based fleet operations. Pratt reached an agreement with new Army Chief of Staff Douglas MacArthur that the Air Corps would assume responsibility for coastal defense (traditionally a primary function of the Army but a secondary, wartime function of the Navy) beyond the range of the Army's Coast Artillery guns, ending the Navy's apparent duplication of effort in coastal air operations. The agreement, intended as a modification of the Joint Action statement on coastal defense issued in 1926, was not endorsed by the Joint Army-Navy Board^{[n 10]} and never had authority other than a personal agreement between the two heads of service. Though the Navy repudiated the statement when Pratt retired in 1934, the Air Corps clung to the mission, and provided itself with the basis for development of long-range bombers and creating new doctrine to employ them.^[28][29]

The formulation of theories of strategic bombing gave new impetus to the argument for an independent air force. Strategic or long-range bombardment was intended to destroy an enemy's industry and war-making potential, and only an independent service would have a free hand to do so. But despite what it perceived as "obstruction" from the War Department, much of which was attributable to a shortage of funds, the Air Corps made great strides during the 1930s. A doctrine emerged that stressed precision bombing of industrial targets by heavily armed long-range aircraft.

This doctrine resulted because of several factors. The Air Corps Tactical School moved in July 1931 to Maxwell Field, Alabama, where it taught a 36-week course for junior and mid-career officers that included military aviation theory. The Bombardment Section, under the direction of its chief, Major Harold L. George, became influential in the development of doctrine and its dissemination throughout the Air Corps. Nine of its instructors became known throughout the Air Corps as the "Bomber Mafia", eight of whom (including George) went on to be generals during World War II. Conversely, pursuit tacticians, primarily Capt. Claire Chennault, Chief of the school's Pursuit Section, found their influence waning because of repeated performance failures of pursuit aviation. Finally, the doctrine represented the Air Corps' attempt to develop autonomy from the General Staff, which enforced subordination of the air arm by limiting it to support of ground forces and defense of United States territory.

Technological advances in bombers[edit]

New bomber types under development clearly outperformed new pursuit types, particularly in speed and altitude, then considered the primary defenses against interception. In both 1932 and 1933, large-scale maneuvers found fighters unable to climb to altitude quickly enough to intercept attacking B-9 and B-10 prototypes, a failure so complete that Westover, following the 1933 maneuvers, actually proposed elimination of pursuits altogether.^[30]

1933 was a pivotal year in the advancement of aviation technology in which the all-metal airplane came of age, "practically overnight" in the words of one historian, because of the availability of the first practical variable-pitch propeller. Coupled with "best weight" design of airframes, the controllable pitch propeller resulted in an immediate doubling of speeds and operating ranges without decreasing aircraft weights or increasing engine horsepower, exemplified by the civil Douglas DC-1 transport and the military Martin B-10 bomber.^[31]

The B-10 featured innovations that became standard internationally for the next decade: an all-metal low wing monoplane, closed cockpits, rotating gun turrets, retractable landing gear, internal bomb bay, high-lift devices and full engine cowlings.^[31][32] The B-10 proved to be so superior that as its 14 operational test models were delivered in 1934 they were fed into the Air Corps mail operation, and despite some glitches caused by pilot unfamiliarity with the innovations,^{[n 11]} were a bright spot. The first action to repair the damaged image of the Air Corps involved the movement of ten YB-10s from Bolling Field to Alaska, ostensibly for an airfield survey, but timed to coincide with the release of the Baker Board's report in July.

The successful development of the B-10 and subsequent orders for more than 150 (including its B-12 variant) continued the hegemony of the bomber within the Air Corps that resulted in a feasibility study for a 35-ton 4-engined bomber (the Boeing XB-15). While it was later found to be unsuitable for combat because the power of existing engines was inadequate for its weight, the XB-15 led to the design of the smaller Model 299, later to become the Boeing B-17 Flying Fortress, whose first flight was at the end of July 1935. By that time the Air Corps had two projects in place for the development of longer-ranged bombers, Project A for a bomber with a ferry range of 5,000 miles (8,000 km), and Project D, for one of a range of up to 10,000 miles (16,000 km).^[33][34] In June 1936 the Air Corps requested 11 B-15s and 50 B-17s for reinforcing hemispheric defense forces in Hawaii, Alaska, and Panama. The request was rejected on the basis that there were no strategic requirements for aircraft of such capabilities.^[35]