Air Warfare. Despite having given birth to the airplane in 1903, the United States was slow to explore the military applications of aviation and had effectively no air arm when war broke out in August 1914. By contrast, Germany, France, and Britain went to war with remarkably efficient aviation establishments, and even Austria‐Hungary and Russia possessed useful air arms. Limited by feeble engines and drag‐producing, externally braced structures, few aircraft in 1914 could carry more than a pilot and an observer. Nevertheless, they played a pivotal role in key early battles, notably the Marne, where British Royal Flying Corps reconnaissance reports were instrumental in turning the Germans back from Paris.

The value of visual reconnaissance was evident from the outset, but when the war deadlocked in the trenches, new missions emerged as designers and manufacturers struggled to improve aircraft performance. By 1916, aerial photography was a crucial element of intelligence: photo mapping provided the detailed charts needed for operational planning; and spotting and adjustment of artillery fire by radio‐equipped aircraft was essential to the massive barrages that dominated the land war on the western front.

The advantages of denying the air to an enemy were obvious, but the first effective means of doing so appeared only in April 1915, when French pilot Roland Garros fielded a device that enabled a machine gun mounted on the engine cowling to fire through the propeller arc, turning his aircraft into a flying gun, a fighter aircraft. After a brief string of aerial victories, Garros was forced down and captured along with his aircraft. Concerned at Garros's success, the German High Command asked Dutch designer Anthony Fokker to copy his device. Instead, Fokker designed his own mechanical synchronization gear (Garros's device was unreliable, relying on steel deflector plates on the blades), which Fokker fitted to his single‐place E‐III monoplane. Fokker's Eindekkers soon reached the front, launching a “Fokker scourge” that lasted until the following spring when superior French Nieuport and British De Havilland fighters appeared. The Germans responded with Albatros scouts, initiating the struggle for air superiority that was central to both world wars.

By the time America entered the war in April 1917, aviation was crucial to victory, particularly on the western front where the opposing industrial powers squared off. The German High Command implicitly recognized this by allocating high‐performance aero engines top production priority in their Amerika Program, designed to produce victory before America's industrial might could be brought to bear. In the event, British and French aircraft production far surpassed Germany's producing air superiority over the trenches and guiding the devastating artillery barrages that broke the German Army. Despite enormous productive capacity, America's intervention in the air war was disappointing. Aside from a handful of Curtiss “Big America” flying boats, America produced no one battleworthy aircraft. The vaunted Liberty engine was produced in impressive numbers, but had mediocre performance and arrived too late. The air component of the American Expeditionary Forces fought well, but mostly in cast‐off French aircraft.

America's most impressive achievement was in training large numbers of aviators and mechanics, but they too arrived late. Most American pilots who saw combat were French‐trained. An important consequence of the U.S. commitment to the air war was the release on the postwar economy of huge numbers of surplus Liberty engines and Curtiss JN‐2 “Jenny” trainers. The results were mixed: on the one hand, the availability of cheap engines and aircraft exposed large numbers of Americans to aviation, notably in the form of touring “flying circuses”; on the other, cheap surplus materiel rendered the civil aviation industry temporarily moribund and stifled technical innovation.

America's huge expanse and thin rail net intervened, creating a larger civil aviation market than the rest of the world combined. The competitive nature of that market led to steady advances in aircraft design, and by the mid‐1930s the best U.S. civil transports could outperform first‐line European bombers and fighters in speed, range, and—most important—useful load as a function of empty weight. This was particularly impressive since, in contrast to Europe and Japan, military aviation subsidies in the United States had all but ceased with the Great Depression.

During the interwar years aerial bombardment was used widely in colonial wars, with the Spanish in Morocco and the Italians in Libya and Ethiopia dropping poison gas on a large scale. U.S. Navy and Marine Corps experiments in the 1920s led to the development of one type of bomber aircraft, the dive‐bomber. These and specialized torpedo bombers comprised the attack complement of aircraft carriers commissioned by the British, American, and Japanese navies. The 1936–39 Spanish Civil War served as a testing ground for aerial combat, with Nazi Germany and Fascist Italy pitted against Soviet Russia. The Luftwaffe perfected its ground support doctrine and revolutionized air‐to‐air tactics with voice radio‐equipped fighters. At the beginning of the conflict, German Ju‐52 transports ferried Spanish regular troops from Morocco to secure Andalusia for the Nationalist rebels in the first decisive use of transport and supply aircraft.

By the late 1930s, few doubted that war was imminent and that airpower would play a major role in its outcome. In 1938, some 80 percent of all aircraft in the world were American civil craft, reflecting the robustness of an industrial and social base that would produce prodigious quantities of aircraft and, of at least equal importance, an inexhaustible flood of pilots, aircrew, and mechanics. But that robustness represented only potential, for the United States possessed only one world‐quality warplane, the Boeing B‐17 bomber, and that only in prototype. At the time of the Japanese attack on Pearl Harbor, America's only battleworthy fighter in service was the Navy F4F Wildcat: not until 1943 did U.S. fighters routinely take the measure of their Axis opponents. In contrast, Britain, Germany, and Japan all entered the war with world‐class fighters, and if prewar Axis bombers lacked the payload‐to‐weight ratios of their American equivalents, they had been battle‐tested in China and Spain.

Only three air forces entered World War II with coherent strategic doctrines: the Luftwaffe with an embryonic theory of strategic bombardment; the Royal Air Force with an air defense doctrine based on radar‐directed intercepts; and the United States Army Air Forces (USAAF) with a well‐articulated theory of strategic daylight precision bombardment. The Luftwaffe, Japanese Navy Air Force (JNAF), and the U.S. Navy's air arm were well trained and equipped to support surface operations; the Royal Navy's Fleet Air Arm was superbly trained, but had mediocre aircraft. Of the rest, the French Armée de l’ Air had high standards of training and some good aircraft, but was shackled to obsolete tactical support doctrine and caught in the middle of a major reequipment program when Germany invaded in May 1940; the Soviet Union's Red Air Force was enormous, but had obsolescent aircraft, mediocre training, and, in the wake of Josef Stalin's purges, a shortage of competent leaders; the Italian Regia Aeronautica was well trained, but with obsolescent equipment and an inadequate industrial base; the Japanese Army Air Force (JAAF) was well trained, but possessed indifferent equipment.

The strategic initiative, sound tactical doctrine, and battleworthy materiel carried the day for Germany and Japan in the initial clashes of the air war, punctuated only by British victory in the Battle of Britain. The Luftwaffe virtually obliterated the Red Air Force at the start of Operation Barbarossa, and Japanese carrier aviation went from victory to victory during the first six months of the Pacific War. The tide turned in the summer of 1942, when U.S. carrier aviation blunted the JNAF's cutting edge at the Battle of Midway just as the British, with copious American aid, were wresting superiority from the Luftwaffe in the Mediterranean. By the eve of the D‐Day landing, heavy losses at Stalingrad, in North Africa, at Kursk, and in Italy had forced the Luftwaffe to concede air superiority everywhere save over Germany, where the hammer blows of RAF Lancaster and Halifax bombers by night and USAAF B‐17s and B‐24s by day forced a maximum defensive effort. The cost in aircraft (which could be replaced) and skilled aircrew (who could not) broke the back of the Luftwaffe. Meanwhile, the JNAF had been destroyed in the Solomons, and the JAAF ruined in the New Guinea. The critical losses were in trained aircrew. Japanese aircraft production increased dramatically and showed remarkable resilience under heavy bombing, but U.S. air superiority was never seriously threatened thereafter, the shock of kamikaze attacks on warships notwithstanding. There is not doubt that airpower was crucial to the defeat of the Axis, but just how and why was—and is—a matter of debate.

Strategic bombing advocates, notably the leaders of the USAAF and its successor, the U.S. Air Force, argued that Germany and Japan were defeated by strategic bombing, or, in the case of Germany, could have been with different targeting priorities. Detractors argued that Nazi Germany fell only to ground invasion, and pointed to the effects of naval blockade on Japan, a resource‐poor island nation, attributing Japanese surrender to shock at the awesome power of the atomic bomb rather than to the economic effects of bombing. Focus on this argument, which formed the backdrop to public debate over America's Cold War military priorities, has obscured awareness of other elements of airpower, notably transport and antisubmarine aviation, both of which were pivotal in World War II; and flight training, which was arguably decisive.

The reality of nuclear deterrence made World War II the last war in which industrialized nations actually tried to destroy one another from the air, and the few massive air campaigns since have been mounted against nonnuclear states by a superpower, a superpower‐led coalition, or a superpower client. The classic early examples are Korea and Vietnam, in which U.S. bombs were pitted against enemy troops and lines of communication. The Soviet Union did commit first‐line equipment and personnel to combat against American air forces—MiG‐15 jet fighters in Korea, and SA‐2 surface‐to‐air missiles plus MiG‐17, MiG‐19, and MiG‐21 fighters in Vietnam—but did so discreetly to avoid overt confrontation. The provision of British and American shoulder‐launched, heat‐seeking antiaircraft missiles to the mujahiddin in opposition to the Soviet invasion of Afghanistan is a parallel example. Israel's air campaigns against its enemies fall into the same category, particularly the 1973 Yom Kippur War, in which U.S.‐provided Israeli aircraft were pitted against Soviet‐designed SA‐6 surface‐to‐air missiles and SPU 23‐4 mobile gun systems which amounted to a technical and tactical extension of the air war over North Vietnam. The most recent example is the coalition air campaign in the 1991 Persian Gulf War.

The operational and tactical parameters of air warfare have changed enormously since 1945 as a result of jet propulsion; helicopters; guided air‐to‐air, surface‐to‐air, and air‐to‐surface missiles; precision‐guided munitions; and, from the 1970s, infrared technology, micro‐miniaturized, transistor‐based, flight control, guidance, and navigation systems; and, finally, stealth aircraft. Indeed, the differences between the attritional air campaigns of World War II, Korea, and Vietnam, and that of the 1991 Gulf War, in which all the elements of change enumerated above came into play for the first time, are so stark that some have argued that the latter represents a revolution in military affairs.

Be that as it may, elements of continuity stemming from the robustness of America's aviation industry are arguably of equal importance. The engineering skill, productive capacity, and the underlying market forces that swamped Axis airpower in World War II are still very much in evidence. To make the point by example, the Boeing B‐52, arguably the most successful bomber ever built, entered service in 1955, played a major role in the Cold War and Vietnam War, and is slated to remain in service into the 2040s. Its immediate predecessor was the Boeing B‐47, a bomber of radical design powered by six jet engines suspended on pylons beneath its thin, swept wings. The B‐47 inspired not only the B‐52s, but the Boeing 707, the first truly successful jet airliner and ancestor of the Boeing airliners that dominate world air traffic today. Many of the high‐capacity civilian air transports called to duty in the 1991 Gulf War as part of the U.S. Civil Reserve Air Fleet were Boeing 747 jumbo jets, descendants of the B‐17 of World War II.
[See also Aircraft Industrialists; Air Force, U.S.: Overview; Procurement: Aerospace Industry; Strategy: Air Warfare Strategy; Tactics: Air Warfare Tactics.]

John F. Guilmartin, Jr.