Air warfare of World War II
was a major component in all theaters of World War II and, together with anti-aircraft warfare, consumed a large fraction of the industrial output of the major powers. Germany and Japan depended on air forces that were closely integrated with land and naval forces; the Axis powers downplayed the advantage of fleets of strategic bombers and were late in appreciating the need to defend against Allied strategic bombing. By contrast, Britain and the United States took an approach that greatly emphasized strategic bombing and tactical control of the battlefield by air as well as adequate air defenses. Both Britain and the U.S. built substantially larger strategic forces of large, long-range bombers. Simultaneously, they built tactical air forces that could win air superiority over the battlefields, thereby giving vital assistance to ground troops. The U.S. Navy and Royal Navy also built a powerful naval-air component based on aircraft carriers, as did the Imperial Japanese Navy; these played the central role in the war at sea.
Pre-war planning
Before 1939, one side operated under largely theoretical models of air warfare. Italian theorist Giulio Douhet in the 1920s summarised the faith that airmen during and after World War I developed in the efficacy of strategic bombing. Many said it alone could win wars, as "the bomber will always get through". The Americans were confident that the Boeing B-17 Flying Fortress bomber could reach targets, protected by its own weapons, and bomb, using the Norden bombsight, with "pickle barrel" accuracy. Japanese aviation pioneers felt that they had developed the finest naval aviators in the world.Air forces
Germany: Luftwaffe
The Luftwaffe was the aerial warfare branch of the Wehrmacht. Under the leadership of Hermann Göring, it was able to learn and test new combat techniques in the Spanish Civil War. The war also led to greater emphasis on anti-air weapons and fighter aircraft due to their ability to defend against enemy bombers. Its advanced technology and rapid growth led to exaggerated fears in the 1930s that helped to persuade the British and French into appeasement. In the war the Luftwaffe performed well in 1939–41, as its Stuka dive bombers terrified enemy infantry units. But the Luftwaffe was poorly coordinated with overall German strategy, and never ramped up to the size and scope needed in a total war, partly due to a lack of military aircraft production infrastructure for both completed airframes and powerplants when compared to either the Soviet Union or the United States. The Luftwaffe was deficient in radar technology except for their usable UHF and later VHF band airborne intercept radar designs such as the Lichtenstein and Neptun radar systems for their night fighters. The Messerschmitt Me 262 jet fighter did not enter service until July 1944, and the lightweight Heinkel He 162 appeared only during the last months of the air war in Europe. The Luftwaffe could not deal with Britain's increasingly lethal defensive fighter screen after the Battle of Britain, or the faster P-51 Mustang escort fighters after 1943.When the Luftwaffe's fuel supply ran dry in 1944 due to the oil campaign of World War II, it was reduced to anti-aircraft flak roles, and many of its men were sent to infantry units. By 1944 it operated 39,000 flak batteries staffed with a million people in uniform, both men and women.
The Luftwaffe lacked the bomber forces for strategic bombing, because it did not think such bombing was worthwhile, especially following the June 3, 1936, death of General Walther Wever, the prime proponent of a strategic bomber force for the Luftwaffe. They did attempt some strategic bombing in the east with the problematic Heinkel He 177A. Their one success was destroying an airbase at Poltava Air Base, Ukraine during the Allied Operation Frantic, which housed 43 new B-17 bombers and a million tons of aviation fuel.
Introduction of turbojet-powered combat aircraft, mostly with the Messerschmitt Me 262 twin-jet fighter, the Heinkel He 162 light jet fighter and the Arado Ar 234 reconnaissance-bomber was pioneered by the Luftwaffe, but the delayed period of their introduction – much of which was due to the lengthy development time for both the BMW 003 and Junkers Jumo 004 jet engine designs—as well as the failure to produce usable examples of their two long-developed higher-power aviation engines, the Junkers Jumo 222 multibank 24-cylinder piston engine of some 2,500 hp, and the advanced Heinkel HeS 011 turbojet of nearly 2,800 lb. of thrust, each of which were meant to power many advanced German airframe design proposals in the last years of the war—meant that they were introduced "too little, too late", as so many other advanced German aircraft designs had been during the later war years.
Although Germany's allies, especially Italy and Finland, had air forces of their own, there was very little coordination with them. Not until very late in the war did Germany share its aircraft and alternative fuel blueprints and technology with its ally Japan, resulting in the Nakajima Kikka jet fighter and the Mitsubishi Shusui rocket fighter, respectively based on the Me 262A and Me 163B—both of which, similarly, came far too late for Japan to improve its defensive aircraft systems, or to make alternative fuels and lubricants.
Britain: Royal Air Force
The British had their own very well-developed theory of strategic bombing, and built the long-range bombers to implement it.Once it became clear that Germany was a threat, the RAF started on a large expansion, with many airfields being set up and the number of squadrons increased. From 42 squadrons with 800 aircraft in 1934, the RAF had reached 157 squadrons and 3,700 aircraft by 1939. They combined the newly developed radar with communications centres to direct their fighter defences. Their medium bombers were capable of reaching the German industrial centre of the Ruhr, and larger bombers were under development.
The RAF underwent rapid expansion following the outbreak of war against Germany in 1939. This included the training in other Commonwealth nations of half of British and Commonwealth aircrews, some 167,000 men in all. It was the second largest in Europe. The RAF also integrated Polish and other airmen who had escaped from Hitler's Europe. In Europe, the RAF was in operational control of Commonwealth aircrews and Commonwealth squadrons although these retained some degree of independence.
The RAF had three major combat commands based in the United Kingdom: RAF Fighter Command charged with defence of the UK, RAF Bomber Command which operated the bombers that would be offensive against the enemy, and RAF Coastal Command which was to protect Allied shipping and attack enemy shipping. The Royal Navy's Fleet Air Arm operated land-based fighters in defence of naval establishments and carrier-based aircraft. Later in the war the RAF's fighter force was divided into two Air Defence of Great Britain for protecting the UK and the Second Tactical Air Force for ground offensive support in the North West Europe campaign.
Bomber Command participated in two areas of attack – the strategic bombing campaign against German war production, and the less well known mining of coastal waters off Germany to contain its naval operations and prevent the U-boats from freely operating against Allied shipping. In order to attack German industry by night the RAF developed navigational aids, tactics to overwhelm the German defences control system, tactics directly against German night-fighter forces, target marking techniques, many electronic aids in defence and attack, and supporting electronic warfare aircraft. The production of heavy aircraft competed with resources for the Army and the Navy, and it was a source of disagreement as to whether the effort could be more profitably expended elsewhere.
Increasingly heavy losses during the latter part of 1943 due to the reorganized Luftwaffe night fighter system, and Sir Arthur Harris' costly attempts to destroy Berlin in the winter of 1943/44, led to serious doubts as to whether Bomber Command was being used to its fullest potential. In early 1944 the UK air arm was put under Eisenhower's direct control where it played a vital role in preparing the way for the Overlord Invasion.
Soviet Union: Soviet Air Force
By the end of the war, Soviet annual aircraft production had risen sharply with annual Soviet production peaking at 40,000 aircraft in 1944. Some 157,000 aircraft were produced, of which 126,000 were combat types for the Voyenno-Vozdushnye Sily or VVS, while the others were transports, trainers, and other auxiliary aircraft. The critical importance of the ground attack role in defending the Soviet Union from the Axis' Operation Barbarossa through to the final defeat of Nazi Germany with the Battle of Berlin resulted in the Soviet military aviation industry creating more examples of the Ilyushin Il-2 Shturmovik during the war than any other military aircraft design in aviation history, with just over 36,000 examples produced.During the war the Soviets employed 7500 bombers to drop 30 million bombs on German targets, with a density that sometimes reached 100–150 tons/ sq kilometer.
United States: Army Air Forces
Before the attack on Pearl Harbor and during the period within which the predecessor U.S. Army Air Corps became the Army Air Forces in late June 1941, President Franklin D. Roosevelt gave command of the Navy to an aviator, Admiral Ernest King, with a mandate for an aviation-oriented war in the Pacific. FDR allowed King to build up land-based naval and Marine aviation, and seize control of the long-range bombers used in antisubmarine patrols in the Atlantic. Roosevelt basically agreed with Robert A. Lovett, the civilian Assistant Secretary of War for Air, who argued, "While I don't go so far as to claim that air power alone will win the war, I do claim the war will not be won without it."Army Chief of Staff George C. Marshall rejected calls for complete independence for the Air Corps, because the land forces generals and the Navy were vehemently opposed. In the compromise that was reached it was understood that after the war, the aviators would get their independence. Meanwhile, the Air Corps became the Army Air Forces in June, 1941, combining all their personnel and units under a single commanding general, an airman. In 1942 the Army reorganized into three equal components, one of which was the AAF, which then had almost complete freedom in terms of internal administration. Thus the AAF set up its own medical service independent of the Surgeon General, its own WAC units, and its own logistics system. It had full control over the design and procurement of airplanes and related electronic gear and ordnance. Its purchasing agents controlled 15% of the nation's Gross National Product. Together with naval aviation, it recruited the best young men in the nation. General Henry H. Arnold headed the AAF. One of the first military men to fly, and the youngest colonel in World War I, he selected for the most important combat commands men who were ten years younger than their Army counterparts, including Ira Eaker, Jimmy Doolittle, Hoyt Vandenberg, Elwood "Pete" Queseda, and, youngest of them all, Curtis LeMay. Although a West Pointer himself, Arnold did not automatically turn to Academy men for top positions. Since he operated independent of theatre commanders, Arnold could and did move his generals around, and speedily removed underachievers.
Aware of the need for engineering expertise, Arnold went outside the military and formed close liaisons with top engineers like rocket specialist Theodore von Karmen at Caltech. Arnold was given seats on the US Joint Chiefs of Staff and the US-British Combined Chiefs of Staff. Arnold, however, was officially Deputy Chief of Staff, so on committees he deferred to his boss, General Marshall. Thus Marshall made all the basic strategic decisions, which were worked out by his "War Plans Division". WPD's section leaders were infantrymen or engineers, with a handful of aviators in token positions.
The AAF had a newly created planning division, whose advice was largely ignored by WPD. Airmen were also underrepresented in the planning divisions of the Joint Chiefs of Staff and of the Combined Chiefs. Aviators were largely shut out of the decision-making and planning process because they lacked seniority in a highly rank-conscious system. The freeze intensified demands for independence, and fueled a spirit of "proving" the superiority of air power doctrine. Because of the young, pragmatic leadership at the top, and the universal glamor accorded aviators, morale in the AAF was strikingly higher than anywhere else.
The AAF provided extensive technical training, promoted officers and enlisted faster, provided comfortable barracks and good food, and was safe, with an American government-sponsored pilot training program in place as far back as 1938, that did work in concert when necessary with the British Commonwealth's similar program within North America. The only dangerous jobs were voluntary ones as crew of fighters and bombers—or involuntary ones at jungle bases in the Southwest Pacific. Marshall, an infantryman uninterested in aviation before 1939, became a partial convert to air power and allowed the aviators more autonomy. He authorized vast spending on planes, and insisted that American forces had to have air supremacy before taking the offensive. However, he repeatedly overruled Arnold by agreeing with Roosevelt's requests in 1941–42 to send half of the new light bombers and fighters to the British and Soviets, thereby delaying the buildup of American air power.
The Army's major theatre commands were given to infantrymen Douglas MacArthur and Dwight D. Eisenhower. Neither had paid much attention to aviation before the war. However the air power advocate Jimmy Doolittle succeeded Eaker as 8th Air Force commander at the start of 1944. Doolittle instituted a critical change in strategic fighter tactics, and the 8th Air Force bomber raids faced less and less Luftwaffe defensive fighter opposition for the rest of the war.
Offensive counter-air, to clear the way for strategic bombers and an eventually decisive cross-channel invasion, was a strategic mission led by escort fighters partnered with heavy bombers. The tactical mission, however, was the province of fighter-bombers, assisted by light and medium bombers.
American theatre commanders became air power enthusiasts and built their strategies around the need for tactical air supremacy. MacArthur had been badly defeated in the Philippines in 1941–42 primarily because the Japanese controlled the sky. His planes were outnumbered and outclassed, his airfields shot up, his radar destroyed, and his supply lines cut. His infantry never had a chance. MacArthur vowed never again. His island-hopping campaign was based on the strategy of isolating Japanese strongholds while leaping past them. Each leap was determined by the range of his 5th Air Force, and the first task on securing an objective was to build an airfield to prepare for the next leap.
Eisenhower's deputy at SHAEF was Air Chief Marshal Arthur Tedder, who had been commander of the Allied Mediterranean Air Command when Eisenhower was in charge of Allied operations in the Mediterranean.