United States Army Air Corps The United States Army Air Corps ( USAAC ) was the statutory forerunner of the United States Air Force . Renamed from the " Air Service " on 2 July 1926 , it was part of the United States Army and the immediate predecessor of the United States Army Air Forces ( USAAF ) , established on June 20 , 1941 . Although abolished as an administrative echelon in 1942 , the Air Corps ( AC ) remained as one of the combat arms of the Army until 1947 . The Air Corps was renamed by the United States Congress largely as a compromise between advocates of a separate air arm and those of the 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 airpower and an autonomous air force between 1926 and 1941 , 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 on 20 June 1941 , when both organizations became subordinate to the new higher echelon . 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 . Creation of the Air Corps . The Air Service had a brief but turbulent history . Created during World War I by executive order , it 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 . 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 . 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 . 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 actuality 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 only minor reforms that included renaming the Air Service to allow it " more prestige . " 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 . 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 . " 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 . 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 . 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 . " 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 only 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 . Five - year expansion program . 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 . 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 were 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 . Organizationally the Air Corps doubled from seven to fifteen groups , but the expansion was meaningless because all were seriously understrength in aircraft and pilots . ( Origin of first seven groups shown here ) Air Corps groups added 1927 – 1937 ¹Disbanded on 20 May 1937 ²Redesignated 17th Attack Group ( 1935 ) , 17th Bomb Group ( 1939 ) 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 . 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 . In 1927 the Air Corps adopted a new color scheme for painting its aircraft , 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 . In the early 1930s the painting of fuselages olive drab was changed to blue , and this motif continued until late 1937 , when all new aircraft ( now all - metal ) were left unpainted except for national markings . 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 . Between 1927 and 1934 , the Curtiss O - 1 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 . Transport aircraft of 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 ) instead of by majors as authorized . The last open - cockpit fighter used by the USAAC , the P - 26 , 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 in a number of crashes and 12 fatalities , the investigating boards that followed 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 one board , 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 . 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 . 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 " . 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 to prove 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 . Doctrinal development . Strategic bombardment in roles and missions . 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 . 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 was desirous of having general assent to 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 only a secondary , war - time 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 and never had authority other than 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 . 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 nation ' 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 . 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 Y1B - 9 and B - 10 prototypes , a failure so complete that Westover , following the 1933 maneuvers , actually proposed elimination of pursuits altogether . The successful development of the Martin B - 10 and subsequent orders after 1935 for more than 150 ( including its B - 12 variant ) continued the hegemony of the bomber within the Air Corps . The B - 10 featured innovations that became standard for the next decade : an all - metal monoplane , closed cockpits , rotating gun turrets , retractable landing gear , internal bomb bay , and full engine cowlings . The superiority of bombers resulted in a 1934 feasibility study for a 35 - ton 4 - engined bomber ( the Boeing XB - 15 ) that , while later found to be unsuitable for combat because the power of existing engines was inadequate for its weight , led to the design of the smaller Model 299 , later to become the 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 , and Project D , for one of a range of up to . 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 . General Staff resistance to Air Corps doctrine . The Army and Navy , both cognizant of the continuing movement within the Air Corps for independence , cooperated to resist it . On 11 September 1935 , the Joint Board , at the behest of the Navy and the concurrence of MacArthur , issued a new Joint Action statement that reasserted the limited role of the Air Corps as an auxiliary to the " mobile Army " in all its missions , including coastal defense . The edict was issued with the intent of shoving an upstart Air Corps back into its place . However , the bomber advocates interpreted its language to mean that the Air Corps could conduct long range reconnaissance , attack approaching fleets , reinforce distant bases , and attack enemy air bases , all in furtherance of its mission to prevent an air attack on America . The lack of inter - service cooperation on coastal defense fostered by the Joint Action Statement continued until the Japanese attack on Pearl Harbor . A month later ( 15 October 1935 ) , the General Staff sought to mitigate criticism of the statement by releasing a revision of Training Regulation TR 440 - 15 " Employment of the Air Forces of the Army " , the doctrinal guide for the Air Corps . In 1934 MacArthur ordered a revision of TR 440 - 15 with the purpose of restating " the Air Corps ' s place in the scheme of national defense and . . . ( to do away with ) . . . misconceptions and interbranch prejudices . " While calling the revision a " compromise " with airpower advocates , the General Staff parroted the conclusions of the Baker and Drum Boards , and reasserted its long - held position ( and that of the Secretary Dern ) that auxiliary support of the ground forces was the primary mission of the Air Corps . TR 440 - 15 did acknowledge some doctrinal principles asserted by the ACTS ( including the necessity of destroying an enemy ' s air forces and concentrating air forces against primary objectives ) and recognized that future wars would probably entail some missions " beyond the sphere of influence of the Ground Forces " ( strategic bombardment ) , but it also completely ignored prioritization of such targets , weakening its effectiveness as doctrine . The Air Corps in general assented to the changes , as it did to other compromises of the period , as acceptable for the moment . TR 440 - 15 remained the doctrinal position of the Air Corps until it was superseded by the first Air Corps Field Manual , FM 1 – 5 " Employment of Aviation of the Army " , on 15 April 1940 . In the fall of 1937 the Army War College ' s course on the use of airpower reiterated the General Staff position and taught that airpower was of limited value when employed independently . Using attaché reports from both Spain and Ethiopia , and endorsed by a senior Air Corps instructor , Col . Byron Q . Jones , the course declared that the Flying Fortress concept had " died in Spain " , and that airpower was useful mainly as " long range artillery . " Air Corps officers in the G - 3 Department of the General Staff pointed out that Jones ' conclusions were inconsistent with the revised TR 440 - 15 , but their views were dismissed by the Deputy Chief of Staff with the comment : " No doctrine is sacrosanct , and of all military doctrines , that of the Air Corps should be the last to be so regarded . " At the same time the General Staff ordered studies from all the service branches to develop drafts for the coming field manuals . The Air Corps Board , a function of the ACTS , submitted a draft in September 1938 that included descriptions of independent air operations , strategic air attacks , and air action against naval forces , all of which the General Staff rejected in March 1939 . Instead it ordered that the opening chapter of the Air Corps manual be a doctrinal statement developed by the G - 3 that " left little doubt " that the General Staff ' s intention was " to develop and employ aviation in support of ground forces . " The Air Corps Board , on the orders of Arnold , developed a secret study for " defense of the Monroe Doctrine " that recommended development of long - range , high altitude , high - speed aircraft for bombardment and reconnaissance to accomplish that defense . The War Department , seeking to stifle procurement of the B - 17 while belatedly recognizing that coordinated air - ground support had been long neglected , decided that it would order only two - engined " light " bombers in fiscal years 1939 through 1941 . It also rejected further advancement of Project A , the development program for a very long range ( VLR ) bomber . In collaboration with the Navy , the Joint Board ( whose senior member was Army Chief of Staff Gen . Malin Craig ) on 29 June 1938 issued a ruling that it could foresee no use for a long range bomber in future conflict . As a direct result , the last planned order of long range bombers ( 67 B - 17s ) was cancelled by Craig and a moratorium on further development of them was put into effect by restricting R & D funding to only medium and light bombers . This policy would last less than a year , as it went against not only the trends of technological development , but against the geopolitical realities of coming war . In August 1939 the Army ' s research and development program for 1941 was modified with the addition of nearly five million dollars to buy five long range bombers for experimental purposes , resulting on 10 November 1939 in the request by Arnold of the developmental program that would create the Boeing B - 29 Superfortress , which was approved on 2 December . Between 1930 and 1938 the Air Corps had obtained a mission in coastal defense that justified both the creation of a centralized strike force and the development of four - engined bombers , and over the resistance of the General Staff lobbied for another mission , strategic bombardment , with which it could persuasively argue for independence from the Army . The cost of the General Staff ' s resistance in terms of preparedness had been severe , however . Its policies had resulted in the acquisition of obsolete aircraft as first - line equipment , stifled design development in the private sector of better types , retarded the development of radar and ordnance , and handicapped training , doctrine , and offensive organization by reneging on commitments to acquire the B - 17 . " From October 1935 until 30 June 1939 , the Air Corps requested 206 B - 17 ' s and 11 B - 15 ' s . Yet because of cancellations and reductions of these requests by the War Department , only 14 four - engine planes were delivered to the air force up to the outbreak of World War II in September 1939 . " GHQ Air Force . A major step toward creation of a separate air force occurred on 1 March 1935 with the activation of a centralized , air force - level command headed by an aviator answering directly to the Army Chief of Staff . Called the " General Headquarters Air Force " , the organization had existed in Army planning since 1924 as a subordinate element of Army General Headquarters , which would be activated to control all Army units in case of war mobilization . In anticipation of military intervention Cuba in 1933 , the headquarters had been created on 1 October but not staffed . The Drum Board of 1933 had first endorsed the concept , but as a means of reintegrating the Air Corps into control by the General Staff , in effect reining it in . Among the recommendations of the Baker Board , established in the wake of the Air Mail scandal , was that the proposals of the Drum Board be adopted : an increase in strength to 2 , 320 aircraft and establishment of GHQ Air Force as a permanent peacetime tactical organization , both to ameliorate the pressures for a separate air force and to exploit emerging capabilities in airpower . In the absence of a general headquarters ( i . e . peacetime ) , GHQ Air Force would report to the General Staff . The War Plans Division of the Army reacted to the recommendations of the Baker Board by insisting that men and modern equipment for seven army divisions be procured before any increase in the Air Corps was begun , and opposed any immediate attempt to bring the Air Corps up to the 1 , 800 plane - strength first authorized in 1926 , for fear of antagonizing the Navy . President Roosevelt approved an open - ended program to increase strength to 2 , 320 aircraft ( albeit without any proviso for funding ) in August 1934 , and Secretary Dern approved the activation of GHQ Air Force in December 1934 . GHQ Air Force took control of all combat air units in the United States from the jurisdiction of corps area commanders , where it had resided since 1920 , and organized them operationally into a strike force of three wings . The GHQ Air Force remained small in comparison to European air forces . On its first day of existence , the command consisted of 60 bombers , 42 attack aircraft , 146 pursuits , and 24 transports , only 40 % of strength in the tables of organization . Administratively it organized the forces into four geographical districts ( that later became the first four numbered air forces ) that paralleled the four field army headquarters created in 1933 . The General Staff perceived its creation as a means of lessening Air Corps autonomy , not increasing it , however , and GHQ Air Force was a " coordinate component " equal to the Air Corps , not subject to its control . The organizations reported separately to the Chief of Staff , the Air Corps as the service element of the air arm , and GHQAF as the tactical element . However all GHQ Air Force ' s members , along with members of units stationed overseas and under the control of local ground commanders , remained part of the Air Corps . This dual status and division of authority hampered the development of Air Corps for the next six years , as it had the Air Service during World War I , and was not overcome until the necessity of expanding the force occurred with the onset of World War II . The commanding general of GHQ Air Force , Maj . Gen . Frank M . Andrews , clashed philosophically with Westover over the direction in which the air arm was heading , adding to the difficulties , with Andrews in favor of autonomy and Westover not only espousing subordination to the Army chain of command , but aggressively enforcing his prohibitions against any commentary opposed to current policy . Andrews , by virtue of being out from Westover ' s control , had picked up the mantle of the radical airmen , and Westover soon found himself on " the wrong side of history " as far as the future of the Air Corps was concerned . Lines of authority were also difficult as GHQ Air Force controlled only combat flying units within the continental United States . The Air Corps was responsible for training , aircraft development , doctrine , and supply , while the ground forces corps area commanders still controlled installations and the personnel manning them . An example of the difficulties this arrangement imposed on commanders was that while the commander of GHQ Air Force was responsible for the discipline of his command , he had no court martial authority over his personnel , which was retained by the corps area commander . Base commanders of Air Corps installations reported to as many as four different higher echelons . The issue of control of bases was ameliorated in 1936 when GHQAF bases were exempted from corps area authority on recommendation of the Inspector General ' s Department , but in November 1940 it was restored again when Army General Headquarters was activated . In January 1936 , the Air Corps contracted with Boeing for thirteen Y1B - 17 Flying Fortress prototypes , enough to equip one squadron for operational testing and a thirteenth aircraft for stress testing , with deliveries made from January to August 1937 . The cost of the aircraft disturbed Secretary of War Harry Woodring , who denied requests for further purchases , so that although the air arm embraced strategic bombing as its primary doctrine after the creation of GHQ Air Force , by 1938 there were still only thirteen on hand . On 18 March 1938 Secretary Woodring implemented a plan that included the purchase of 144 four - engine bombers , but approval was reversed in July following the moratorium against the long - range bomber program issued by the Joint Board . The purchase of 67 B - 17s ( five squadrons ) in FY 1940 as an increment of the Woodring program , using carryover funds , was cancelled by Craig . The moratorium also resulted from the enmity of the Navy incurred by the Air Corps on 12 May 1938 when it widely publicized the interception of the Italian ocean liner " Rex " by three B - 17s while it was off - shore of New York City . Possibly under pressure from the Navy , Craig placed a limit of on all future off - shore flights by the Army . The services together issued a revised Joint Action statement in November reasserting that the mission of the Air Corps in coastal defense was only for supporting the Navy if called upon to do so , while simultaneously authorizing for the Navy the long - range shore - based coastal patrol mission denied the Air Corps . Westover , who stridently opposed cancellation of the Woodring program , was killed in an air crash on 21 September 1938 and was succeeded by Arnold . Even with the doctrine of strategic bombardment as its priority , the Air Corps belatedly sought to modernize its tactical combat force under GHQ Air Force , bringing into service the Northrop A - 17 and Douglas B - 18 Bolo in 1936 , the Seversky P - 35 in 1937 , and the Curtiss P - 36 in 1938 . However all of these aircraft were obsolete by the time they came into service , and the outbreak of war in Europe spurred development of more capable types . By October 1940 , over a year before the United States was drawn into the war , every piston - driven single - seat fighter eventually used by the USAAF during World War II was in flight test except the Republic P - 47 Thunderbolt . However , the press of the enormous tasks confronting the Air Corps and the primacy of strategic bombing doctrine meant that development of a long - range capability for these new single - engined fighters was not undertaken until combat losses to bombers forced the issue . Problems with unity of command . Arnold , at the direction of President Roosevelt in January 1939 , oversaw an expansion of the Air Corps that saw it double in size from 15 to 30 groups by the end of 1940 . The separation of the combat organization ( GHQ Air Force ) from the logistic organization ( Air Corps ) created serious problems of coordination nearly identical to the Division of Military Aeronautics / Bureau of Aircraft Production dual - authority mess of World War I . In March 1939 , with the replacement of Andrews as commander of GHQ Air Force by Maj . Gen . Delos C . Emmons , Arnold was also nominally assigned to " supervise " the tactical force , but divisions were not entirely resolved . On 5 October 1940 , Arnold drew up a proposal for creating an air staff , unifying the air arm under one commander , and giving it autonomy with the ground and supply forces — a plan which was eventually adopted in March 1942 — and submitted it to Chief of Staff George C . Marshall , but it was immediately opposed by the General Staff in all respects . Instead , the two organizations were separated again by a directive from Marshall on 19 November 1940 . Army GHQ was activated ( more than five years after the activation of GHQ Air Force ) and GHQ AF placed under it . Its logistical and training structure remained under direct control of the chief of staff and its airfields under corps commanders . However Arnold had joined the General Staff as acting " Deputy Chief of Staff for Air " on 11 November 1940 , a position that enabled him to coordinate the two sections of the air arm until the organizational problems were repaired . Even so , Maj . Gen . George H . Brett , acting Chief of Air Corps in Arnold ' s absence , denounced the plan as " disastrous in war " . The problems engendered by the lack of unity of command were further exacerbated by the assignment of GHQ Air Force to Army GHQ . Emmons , who had begun his tour junior to Arnold , was promoted to lieutenant general to make him equal to the commanders of the field armies also controlled by Army GHQ . This forced him to report to and act under an inferior in rank ( both Arnold and Brett were major general s ) . On 20 June 1941 , in an attempt to end the divisions , the War Department revised Army Regulation 95 - 5 to create the Army Air Forces with the Air Corps and the Air Force Combat Command ( a redesignation of General Headquarters Air Force ) as its major components , authorized an Air Staff to manage planning and execution of expansion of the air arm , and named Arnold as Chief of the Army Air Forces . It did not , however , end the dual chain of command , as air units of Air Force Combat Command still reported to Army GHQ as well as Headquarters AAF . During World War II the role of the Air Corps changed again . On 9 March 1942 , War Department Circular 59 abolished Army GHQ and organized the Army into three autonomous components : the Army Air Forces , the Army Ground Forces , and the Services of Supply , each with a commanding general reporting to the Chief of Staff . The Office of Chief of Air Corps ( OCAC ) was abolished as well ( as was Air Force Combat Command ) and the functions of the Air Corps transferred to the AAF , reducing it to a combat arm ( Infantry and the other combat arms also had their chiefs abolished and functions transferred to the Army Ground Forces ) . The Congress did not disestablish the Army Air Corps until 26 July 1947 , with the passage of the National Security Act of 1947 ( 61 " Stat . " 502 ) . Most members of the Army Air Forces , however , also remained members of the Air Corps . In May 1945 , 88 percent of officers serving in the Army Air Forces were commissioned in the Air Corps , while 82 percent of enlisted members assigned to AAF units and bases had the Air Corps as their combat arm branch . Modernization and expansion of the force . New aircraft . The Air Corps tested and employed a profusion of pursuit , observation , and bomber aircraft during its 15 - year history . The advent of the all - metal monoplane , enclosed cockpits , retractable landing gear , enclosed bomb bays , and the emergence of strategic bombardment doctrine led to many designs in the mid and late 1930s that were still in use when the United States entered World War II . Among the key technology items developed were oxygen and cabin pressurization systems , engine superchargers ( systems essential for high - altitude combat ) , advanced radio communication systems , such as VHF radios , and the Norden bombsight . As a further consequence of the Air Mail scandal , the Baker Board reviewed the performance of Air Corps aircraft and recognized that civilian aircraft were far superior to planes developed solely to Air Corps specifications . Following up on its recommendation , the Air Corps purchased and tested a Douglas DC - 2 as the XC - 32 , which subsequently became the flying headquarters of Gen . Andrews . The DC - 2 so exceeded Air Corps specifications that 17 were purchased under the designation C - 33 to equip the first permanent transport unit , the 10th Transport Group , activated in June 1937 at Patterson Field in Ohio . In 1939 the Air Corps recognized that it might soon require large numbers of modern air transports for use in war and purchased 35 DC - 2 / DC - 3 hybrids , designated the C - 39 . After the fall of France , the Air Corps in September 1940 ordered 200 untried and unproven C - 46 transports from Curtiss - Wright and 545 C - 47 Skytrain s , the forerunner of the more than 10 , 000 C - 47s and related variants that served in World War II . Notable fighters developed during the late 1930s and early 1940s were the P - 39 Airacobra ( first flown April 1938 ) , P - 40 Tomahawk ( October 1938 ) , P - 38 Lightning ( January 1939 ) , P - 51 Mustang ( October 1940 ) , and P - 47 Thunderbolt ( May 1941 ) . Technological development of fighters occurred so rapidly that by December 1941 both the P - 39 and P - 40 were approaching obsolescence , even though both had been in production less than 18 months . Bombers developed during this period were the A - 20 Havoc ( first flown October 1938 ) , B - 25 Mitchell ( January 1939 ) , B - 24 Liberator ( December 1939 ) , and B - 26 Marauder ( November 1940 ) . Except for the B - 24 , P - 47 , and P - 51 , all of these had production deliveries that began before the AAF came into being in June 1941 . Three other long - range bombers began development during this period , though only mock - ups were produced before World War II : the B - 29 ( study begun in 1938 ) , the B - 32 Dominator ( June 1940 ) , and the B - 36 Peacemaker ( April 1941 ) . Expansion of the Air Corps . In a special message to Congress on 12 January 1939 , President Roosevelt advised that the threat of a new war made the recommendations of the Baker Board inadequate for American defense and requested approval of a " minimum 3 , 000 - plane increase " for the Air Corps . On 3 April 1939 , Congress allocated the $ 300 million requested by Roosevelt for expansion of the Air Corps , half of which was dedicated to purchasing planes to raise the inventory from 2 , 500 to 5 , 500 airplanes , and the other half for new personnel , training facilities , and bases . In June the Kilner Board recommended several types of bombers needed to fulfill the Air Corps mission that included aircraft having tactical radii of both 3 , 000 miles ( modified in 1940 to 4 , 000 ) and 2 , 000 miles . Chief of Staff Craig , long an impediment to Air Corps ambitions but nearing retirement , came around to the Air Corps viewpoint after Roosevelt ' s views became public . Likewise , the War Department General Staff reversed itself and concurred in the requirements , ending the brief moratorium on bomber development and paving the way for work on the B - 29 . Over the winter of 1938 – 1939 , Arnold transferred a group of experienced officers to his headquarters as an unofficial air staff to lay out a plan that would increase the Air Corps to 50 , 000 men by June 1941 . The expansion program of the Air Corps was characterized by repeated upward revision of goals for increasing aircraft production , total combat units , the training of new personnel , and construction of new bases . New combat groups were created by detaching cadres from the existing 15 Regular groups to provide the core of the new units , with the older groups providing the basis for an average of three new groups . Graduates of an expanded flight training program filled out the new groups and replaced the experienced personnel transferred from the older groups , resulting in a steady decline in the overall level of experience in the operational units . In essence , groups " self - trained " to proficiency standards set by training directives from the GHQAF . Unable to keep pace with the revised programs for expansion of combat groups , unit tactical training for all groups suffered from a shortage of equipment ( particularly combat aircraft ) , an unavoidable preoccupation with administrative details during organization , and a lack of training facilities , especially bombing and gunnery ranges , leaving a " vast gap between the desired status of training in combat units and their actual status immediately prior to . . . Pearl Harbor . " The initial " 25 - Group Program " for air defense of the hemisphere , developed in April 1939 , called for 50 , 000 men ( 12 , 000 pilots ) . Its ten new combat groups were activated on 1 February 1940 . Following the successful German invasion of France and the Low Countries in May 1940 , a " 54 - Group Program " was approved on 12 July , although funding approval could not keep pace and only 25 additional groups were activated on 15 January 1941 . An " 84 - Group Program " , with an eventual goal of 400 , 000 men by 30 June 1942 , was approved on 14 March 1941 , although not publicly announced until 23 October 1941 . In addition to unit training and funding problems , these programs were hampered by delays in acquiring the new infrastructure necessary to support them , sites for which had to be identified , negotiated and approved before construction . The General Staff again was unwilling to assign any of this work to the Air Corps , and instead detailed it to the overtaxed Quartermaster Corps . When the QMC failed to put new air bases in place in either an efficient or timely manner , the Corps of Engineers was then assigned the task , although it continued to implement the policies already in place . When war broke out in September 1939 the plan was only halfway to its goal in manpower , and the Air Corps had only 800 first - line combat aircraft , 700 of which were declared obsolete by December 1941 . Two - thirds of its officers were second lieutenants whose only flying experience was their flight training . The Air Corps had 17 major installations and four depots , and most of its 76 airfields were co - located at civil airports or were small fields on Army posts . The acceleration of the expansion programs resulted in an Air Corps of 156 airfields and 100 , 000 men by the end of 1940 . Twenty civilian flight schools and eight technical training schools were contracted to provide additional training facilities , and on 10 August 1940 , Pan American Airways was contracted to provide meteorological and navigation training at Coral Gables , Florida , until military schools could be established . Procurement of aircraft remained a significant problem for the Air Corps until the eve of war , because of diversion of production to the Allies . On 16 May 1940 , with the fall of France imminent , President Roosevelt delivered an address to Congress calling for a supplemental appropriation of nearly a billion dollars and the manufacture of 50 , 000 aircraft a year for the armed forces ( 36 , 500 of them for the Air Corps ) . Eighteen months later the AAF still had only 3 , 304 combat aircraft ( only 1 , 024 overseas ) , and 7 , 024 non - combat aircraft , of which 6 , 594 were trainers . Its command staff increased in October 1940 to 24 with the addition of 15 new general officer billets . By the date the Air Corps became part of the AAF nine months later , it had 33 general officers , including four serving in observer roles to the Royal Air Force . At this stage , public opinion support of airpower reached unprecedented highs , but Arnold made a decision to postpone any attempts to exploit the opportunity to push for an independent Air Force . Assured of a free hand by Marshall , Arnold thought that it would " be a serious mistake to change the existing setup " in the midst of the crucial expansion effort , which in less than five years would be more than 100 times its June 1939 size in personnel ( much of it highly trained technically ) alone . Organization of the Air Corps . Army Air Corps , 1 March 1935 . This list of units is a snapshot of the Air Corps on the date of activation of General Headquarters Air Force . Except for the addition of reconnaissance ( formerly observation ) squadrons to the three bombardment groups in September 1936 , and the May 1937 exchange of the 12th Observation Group ( disbanded ) for the 10th Transport Group ( activated ) , the organization of the Air Corps shown here remained essentially unchanged until activation of the first expansion groups on 1 February 1940 . ( Brig . Gen . Henry H . Arnold , March Field , California ) ( Brig . Gen . H . Conger Pratt , Langley Field , Virginia ) ( Col . Gerald C . Brant , Barksdale Field , Louisiana ) ( Lt . Col . Delos Emmons , Fort Shafter , Hawaii ) ( Lt . Col . William C . McChord , Albrook Field , Panama Canal Zone ) Annual strength . Strength as of 30 June of each year Lineage of the United States Air Force . < nowiki > * < / nowiki > The Air Corps became a subordinate component of the Army Air Forces on 20 June 1941 , and was abolished as an administrative organization on 9 March 1942 . It continued to exist as one of the combat arms of the Army ( along with infantry , armor , and artillery ) until abolished by reorganization provisions of the National Security Act of 1947 ( 61 " Stat " . 495 ) , 26 July 1947 .