World War II, air war, European Theater strategic operations

See also: World War II, air war, Allied offensive counter-air campaign

See also: World War II, air war, Mediterranean and European tactical operations

See also: World War II, air war, Pacific Theater strategic operations

See also: Battle of the Atlantic

British and American strategic bombing advocates had different paradigms of what is, today, called strategic strike. This resulted in different aircraft designs, training, targeting, and operational techniques.

It should be understood that the European Theater strategic campaign began with small British raids in 1940, during the Battle of Britain, but major bombing programs continued from 1942 to the end of the war. During that time, there were various parallel efforts, such as the 1944 offensive counter-air campaign and the support of ground operations, including preparing for invasions as well as well as close air support and battlefield air interdiction.

Doctrine for strategic bombing

Strategic bombing advocates on all sides believed that it was possible, with the weapons and tactics of the Second World War, to break the morale of the enemy population by what are now called countervalue attacks. Postwar studies, as well as observations during the most intense bombing of Britain, showed this simply was not the case.

In a large-scale nuclear countervalue attack, civilian morale would be irrelevant, for it is hard to have morale when one is part of a mushroom cloud.

British and American strategic bombing advocates had different paradigms of what is, today, called strategic strike. This resulted in different aircraft designs, training, targeting, and operational techniques.

Both did agree that the most effective attacks saturated the German defenses, by putting as many bombers over target as quickly as possible. For every 100 sorties in 1944, 25 bombers were hit by flak; most managed to hold formation and return--stragglers usually crashed or were shot down by fighters.

Air targeting officers did not see enemy cities as mere passive housing tracts filled with innocent civilians but rather as the nerve centers of warmaking and as active fortresses that fought back vigorously and which often inflicted more damage than they received.

The airmen, while delighted with the greatly enhanced importance of air power implied by the emphasis on tactical air supremacy, in fact had a quite different doctrine regarding how air power could best be applied. It was "strategic bombing." Do not be misled by tanks and artillery and infantry, they insisted- -that was ancient history. The war could be won hundreds or thousands of miles behind the front lines--an invasion would be unnecessary because the bombers alone could defeat Germany and Japan. Modern warfare depended upon industrial production in large, fixed, visible factories, oil refineries and electric power stations. As Lovett explained, "Our main job is to carry the war to the country of the people fighting us--to make their working conditions as intolerable as possible, to destroy their plants, their sources of electric power, their communications system."

U.K

The Royal Air Force (RAF) had its own strategic bombing campaign, under Sir Arthur Harris, often referred to as "Bomber Harris". He was a strong advocate of the importance of strategic bombing.

A division of labor was agreed on whereby the RAF flew missions at night with Vickers Wellington bombers, which carried more bombs but had much less defensive capability than the B-17. Later in the war, the British also used the Avro Lancaster. The better-protected U.S. bombers flew daytime missions.

The British developed some new tactics. The Pathfinder squadrons flew the twin-engine De Havilland Mosquito bombers, going in at low altitudes to drop incendiaries that would guide the Lancasters coming later and higher with heavier bomb loads. This greatly increased the accuracy of nighttime bombing. The Dambusters took out a number of major German dams with multi-ton bombs designed for the purpose by Barnes Wallis; these were dropped by Lancasters from an altitude of only 60 feet.

In some raids, the British and Americans took turns, with the RAF pounding the place by night and the USAF doing the same by day. One such attack almost totally destroyed Hamburg with about two weeks of unremitting bombing, actually causing more damage and more deaths than Hiroshima. Another, for which Harris and others were vilified by critics after the war, destroyed Dresden.

U.S.

Marshall and King did not fully accept the doctrine of strategic bombing. They insisted that control of the air would always be supplementary, and they much preferred tactical air. Furthermore, they denied that strategic bombing of the enemy's industrial strength would be decisive in warfare. Marshall accepted AWPD-1 as a blueprint for airplane acquisition and force levels (it proved astonishingly accurate), but refused to believe that strategic bombing could be decisive, noting "an almost invariable rule that only armies can win wars." Secretary of War Stimson, who usually backed Marshall 100%, disagreed this time: "I fear Marshall and his deputies are very much wedded to the theory that it is merely an auxiliary force."

The debate between the AAF and the Army and Navy resulted in a compromise: both strategic and tactical air power would be used. The production of planes (AAF, Navy, Marines) was split about equally between strategic and tactical air, with 44% going to strategic bombers (especially the B-17 and B-29), 24% going to tactical ground-support and interdiction bombers (medium land-based Army and Marine, and light carrier-based Navy planes), and 20% to fighters (which could either escort strategic bombers or be used as tactical air.) The remainder went for transports, trainers, and unarmed reconnaissance planes. Arnold kept to the compromise, and did provide Marshall with ample tactical air power, but with the proviso that his airmen would always decide on how, when and where it was to be used. In the boldest move for AAF autonomy, Arnold gained almost complete control over the strategic bombing campaigns against Japan and Germany. Nimitz and MacArthur, therefore, shared control of the Pacific war with Arnold in Washington, while Eisenhower shared control of the European war with Arnold.

In August, 1941, the AAF devised AWPD-1, its plan to win the war through air power alone (an appendix discussed tactical support for an invasion, should that prove necessary.) AWPD-1 read like an engineering document, and focused what were believed to be the centers of gravity (military)|centers of gravity]] of the German war economy. It listed 154 German targets in order of priority (electric power, railroad yards and bridges, synthetic oil plants, aircraft factories). By assuming half the bombs would land within 400 yards of their targets, it concluded that 3,800 bombers could finish the job in six months time. A total of 62,000 combat planes, and 37,000 trainers would have to be built.

AWPD-42, completed a year later, provided more tactical air power, proposed a detailed strategic air war against Japan, and reaffirmed the same German targets (plus submarine yards). The summit conference at Casablanca in January, 1943, accepted the basic plan of AWPD-42: Germany and Japan would be the targets of massive strategic bombing that would either force their surrender or soften them up for an infantry invasion.

The Pacific operation was essentially American. While there was a generally shared doctrinal concept, the problems of conducting effective strategic bombing was different: the supporting actor award went to the amphibious warriors of the United States Navy, United States Marine Corps, and United States Army, who captured and rebuilt the airfields needed to reach the Japanese home islands.

Had the war in Europe lasted longer, although some claim the nuclear weapons were saved, for "racial" reasons, against Japan, had the weapons been ready and there was not the same confidence in ground victory, they would have been used. For that reason, the article World War II, Air War, nuclear warfare deals first with the concept of nuclear warfare as then understood and the Manhattan Project to develop them. It deals with the decision to use them on Japan, and the mechanics of that operation, because Japan was the only available target when the first bombs were available.

Russian

The Russians never spent significant development on long-range aviation. Perhaps their outstanding design was the Il-2 Stormovik, a heavily armored ground support and antitank aircraft, which was an inspiration for the much later U.S. A-10 Thunderbolt II.

One Russian group that was quite effective were the 588th Night Bomber Regiment or Night Witches. They flew slow obsolete biplanes designed as crop dusters, mainly in harassing raids on German ground forces.

German

Hitler was insistent on bombers having tactical capability, which meant dive bombing at the time, a maneuver impossible for any heavy bomber of the time. His aircraft had limited effect on Britain for a variety of reasons, but low payload certainly was among them. When the Luftwaffe could operate from bases in France, it compensated for their short range.

Japan

Japan never did more than experiment with long-range bombers; they had no operational force.

Technology

Significant areas of technology included aircraft, navigational and bombing equipment, bombs, and defensive systems.

Manned bombers

Strategic bombers in Europe

Country and aircraft	Manufacturer(s)	Features and liabilities
German Ju-88	German	Light bombload, medium range, surviable
German Do-17	Dutch	Moderate bombload, medium range
U.K. Avro Lancaster	U.K.	Heaviest bombload in Europe; little defense
U.S. B-17 Flying Fortress	U.S.	Light bombload in its class, strong defense
U.S. B-24 Liberator	U.S.	Moderate bombload, long range

Unmanned missiles

Hitler tried to sustain morale by promising that "secret weapons" would turn the war around. He did indeed have the weapons. The first of 9,300 V-1 flying bombs hit London in mid- June, 1944, and together with 1,300 V-2 rockets caused 8,000 civilian deaths and 23,000 injuries. Although they did not seriously undercut British morale or munitions production, they bothered the British government a great deal--Germany now had its own unanswered weapons system. Using proximity fuzes, British ack-ack gunners (many of them women) learned how to shoot down the 400 mph V-1s; nothing could stop the supersonic V-2s. The British government, in near panic, demanded that upwards of 40% of bomber sorties be targeted against the launch sites, and got its way in "Operation CROSSBOW." The attacks were futile, and the diversion represented a major success for Hitler. In early 1943 the strategic bombers were directed against U- boat pens, which were easy to reach and which represented a major strategic threat to Allied logistics. However, the pens were very solidly built--it took 7,000 flying hours to destroy one sub there, about the same effort that it took to destroy one-third of Cologne. The antisubmarine campaign thus was a victory for Hitler.

Every raid against a V-1 or V-2 launch site was one less raid against the Third Reich. On the whole, however, the secret weapons were still another case of too little too late. The Luftwaffe ran the V-1 program, which used a jet engine, but it diverted scarce engineering talent and manufacturing capacity that were urgently needed to improve German radar, air defense, and jet fighters. The German Army ran the V-2 program. The rockets were a technological triumph, and bothered the British leadership even more than the V-1s. But they were so inaccurate they rarely could hit militarily significant targets.

Furthermore, the program used up scarce technical resources that could have gone into the development of air defense weapons like proximity fuzes and "Waterfall," a deadly surface-to-air missile. The secret weapon of greatest threat to the Allies was a first-generation jet aircraft that could outfly Allied fighters and shoot down bombers. The Messerschmitt ME-262 prototype flew in 1939, but was never given high priority until too late. Hitler never understood air power; his personal interference repeatedly delayed the jets. First he proclaimed they would not be necessary, then insisted they be redesigned as bombers to make retaliation raids against London. The Luftwaffe would have been a much more deadly threat if it built ten thousand jets; it only made one thousand and they rarely flew combat missions.

Strategically significant fighters

Strategic fighters in Europe

Country and aircraft	Theater	Features and liabilities
U.S. P-51 Mustang	U.S. airframe, U.K. engine	Escort fighter with range to heart of Germany
German Me-262	Germany	first-generation jet fighter faster than any other operational aircraft

Defensive systems

Britain was the first to develop an integrated air defense system, for the Battle of Britain, but Germany responded with the Kammhuber line. Both sides fought an invisible battle of attack and defense in electronic warfare.

Targeting

British targeting doctrine emphasized cities, while U.S. targeting was more on specific industries. The British bombers carried a heavier bombload but had less defensive capability, so they were suited more for night bombing of large areas. While some British leaders, such as Chief of Air Staff Sir Charles Portal later urged RAF Bomber Command to go after specific target systems, Sir Arthur Harris, general officer commanding Bomber Command, was committed to the "dehousing" targeting model proposed by Lord Cherwell.

Urban attacks

In Germany the targeted cities contained 25 million people before the war; the damage was done primarily in 1944-45 when at least 5 million people had evacuated. Of all 75 million civilians in Germany, 1/2 of one percent (300,000) were killed, another 1% were injured, 10% were dehoused, 25% deprived of gas, water and electricity for varying periods, and 100% were inconvenienced by fear, shortages and disruptions. The bombing campaigns did not target civilians outside large cities, or their food supplies. (Tactical air sometimes did strafe passenger trains; the pilots could not tell whether they carried civilians or soldiers.)

The main emphasis was on large cities for several reasons. Pragmatically, the target had to be large enough to hit. Small cities or factories in the forests were extremely hard to bomb from high altitude. Big bombers flew high when it was discovered the risk from flak was near 100% at 8,000 feet, but "only" 25% at 20,000 feet. Even at great height bombers often had to zigzag and rush their bombing run lest the ground crews get their range. The RAF noticed that when flak was light, 41% of its bombs hit near the target, compared to only 32% when flak was heavy.

The large cities were prime targets because they contained most of the enemy's munitions factories, railroad yards, government offices and communications centers. According to Air Force doctrine, only a small fraction of the enemy population was targeted for attack--notably the centers of war production, communications, command and control.

Civilians were repeatedly warned (by billions of leaflets) to evacuate those cities, or else they would be considered as willing participants in the enemy war effort. Without its cities, an enemy army would lose its munitions supply and its power of movement. As early as 1916, and certainly by the 1930s, it was a well-recognized concept that "civilians" who worked in munitions factories were as much a part of the war effort as soldiers in the front lines, and were legitimate targets. The munitions workers themselves felt that way, as they glanced at posters or listened to speeches from visiting dignitaries telling them how essential they were to the war. They were "non-peaceable" civilians. The efforts of civilian munitions workers in the cities across the globe were largely responsible for deciding who would win the war.

Some raids caused "firestorms," notably Hamburg and Kassel in 1943, Dresden and Tokyo in 1945. Firestorms were very hard to start; they occurred in unpredictable situations when a number of scattered fires suddenly combined into a tornado-like inferno which sucked up all the oxygen (including the oxygen in underground shelters). At Hamburg 40,000 people suffocated inside shelters. Tens of thousands died in Dresden, but the railway yards, munitions factories and military bases were mostly undamaged. At Hamburg, full factory production resumed in a matter of weeks, but upwards of a million civilians fled the city.

Petroleum, oil and lubricants; other components

Fuel, in particular, is essential to air operations; a shining new airplane with empty tanks is useless. Originally, the Allied strategic bombing programs spread their effort over multiple industries, never sufficiently disrupting any given one sufficiently to break the system.

There was criticism, especially of "panacea" targeting, by some air leaders, especially Arthur Harris. Such targets included ball bearings (e.g., Schweinfurt) and oil. Especially toward the end of the war, there was strong intelligence, such as ULTRA intercepts, that a given side was almost out of some resource. The sensitivity of the intelligence source, however, preventing sharing the conclusive data with operational commanders and their targeting staffs.

It is easy to assume that both sides knew then as much as they know now. Much of our vulnerability analyses came from the U.S. Strategic Bombing Survey interviews, which certainly gave insights not available at the time.

Chronology

In 1942, the first attacks were essentially probes, which also taught a great deal. Unescorted bombers were not nearly as capable at self-defense, during the day, than the U.S. had believed.

Recognizing the effectiveness of the defense, the 1943 offensive focused on directly engaging enemy fighters, often in specialized operations without bombers. Bombing concentrated on the aircraft industry, key subcomponents such as ball bearings, and fuel, although the Allies never stayed on any one subsystem long enough to disable it. Especially after Albert Speer became German Minister of Armaments, production actually rose for a time, as factories dispersed and went underground.

Speer figured out the antidote to air raids in 1943-- disperse critical factories outside the major cities. The V-1 and V-2 missiles were built in caves and underground factories that were largely immune from bombs. However, many local Nazi leaders, fearful that Speer's plans to build new factories in their villages would attract air raids, dragged their feet and effectively sabotaged Speer's program. Dispersal, furthermore, made the Germans even more reliant on their fragile transportation system. With railroad yards hit every week, it took longer and longer for parts to reach underground assembly factories, and it became more and more difficult to move the final product to the front lines.

It was well into 1945 when a serious attempt was made to concentrate on oil and knock out that system, not without opposition from the head of RAF Bomber Command.

1942

The American strategic bombing campaign against Germany was operated in parallel with RAF Bomber Command, which fervently believed in its own version of strategic bombing doctrine. The AAF bombed during the day, the RAF at night, when interception was difficult. Nightime navigation was so poor that the RAF quickly gave up precision bombing; their real target was the morale of the people who lived in the largest cities.

According to Air Marshal Sir Arthur Harris, General Officer Commanding of RAF Bomber Command massive nightly raids would eventually burn out all the major German cities. The populace might survive in shelters, but they would be "dehoused", and lose confidence in the Fuehrer, which would lead to loss of German will to resist. Furthermore, the factories and railroad system would eventually be burned out as well. The British were willing to spend 30% of their GNP on Bomber Command, in order to weaken Germany, gain revenge, and avoid the high infantry casualties such as the Soviets were enduring. Strategic bombing did "dehouse" 7.5 million Germans, but it hardly mattered, for the target cities had a surplus of housing (because most young men were away the army, most civilians had evacuated to the countryside, and all Jews sent to death camps and their apartments seized.)

As the U.S. Strategic Bombing Survey reported after the war, "Allied bombing widely and seriously depressed German morale, but depressed and discouraged workers were not necessarily unproductive workers." The German civilian air defense system enrolled 22 million volunteers, supervised by 75,000 full-time officials. Focusing on basement shelters in residential districts in the cities, the Germans built interconnected passageways, painted on fire retardants, and stored emergency supplies. The Gestapo, making tens of thousands of arrests, made certain that discontent was kept unfocused. Bombs did occasionally damage factories, but fast repairs were made. Rare indeed was the bomb dropped from 20,000 feet that destroyed a steel machine tool, especially when the bombadier had only the vaguest idea where it was or where he was.

Gaining Allied air supremacy in Europe, 1943

In late 1943 the AAF suddenly realized the need to revise its basic doctrine: strategic bombing against a technologically sophisticated enemy like Germany was impossible without air supremacy. While strategic bombing against the aircraft and petroleum industry helped, to achieve air supremacy in a reasonable time, that had to be done with a deliberate attack on the Luftwaffe. In modern terms, General Arnold realized that it was necessary to conduct an offensive counter-air campaign. See World War II, Allied offensive counter-air campaign.

In January 1943, Berlin decreed the full mobilization of every German. Civilian jobs not essential to the war effort were to be abolished. Hitler declared "total war. Goebbels intensified the propaganda barrage, and the Nazi Party, the Gestapo and the SS turned the screws. As Field MarshalGerd von Rundstedt proclaimed:

The Fuhrer has decreed: that our conduct of war must become fanatical since the battle has touched German soil along broad sectors, and German cities and villages are being turned into battlegrounds....Every bunker, every block in a German city, and every German village must be turned into a fortress against which the enemy will either bleed to death or its garrison be buried in man-to-man combat.

1944

1944 operations mixed preparation for the invasion, continued strategic attacks, and increased battlefield air interdiction.

Countervalue

A typical attack against both population and industry was the case of Ludwigshaven, a city of 150,000 population on the Rhine River near Heidelberg. Its two giant I.G. Farben plants, covering 1200 acres and employing 40,000 workers, produced much of Germany's ammonia, synthetic rubber, synthetic oil and other vital chemicals; its railroad yards were important too, and hundreds of small shops and factories produced war materials, such as diesel engines for submarines. The Luftwaffe ringed it with 180 high-powered flak guns. Thirteen thousand Allied bombers hit the city in 121 separate raids during the war, of which 56 succeeded in hitting the Farben plant. Those 56 raids dropped 53,000 bombs each containing 250 to 4,000 pounds of high explosives, plus 2.5 million 4-pound magnesium incendiary bombs. (The bombers also dropped millions of warning leaflets, plus counterfeit ration coupons.) Clouds (or protective smoke) usually covered the target, so "pathfinder" planes identified the general vicinity with flares, and the bombardiers unloaded on the flares.

This sort of "area bombing" was not especially accurate: out of 1,700 bombs dropped on January 7, 1944, only 127 hit the Farben plank. On average, 1.4 tons of bombs hit each acre of the Farben complex (but buildings covered only 25% of the ground, so most hit open land.) Bombing accuracy improved with experience; in a January, 1945, raid, 1,000 high explosive bombs and 10,000 incendiaries fell within the factory fences, starting 10 large, 30 medium and 200 small fires. Bombs that missed the factory that day ruined 354 residences and dehoused 1,800 people. The shelter system worked well, for only five people on the ground were killed. By war's end most dwellings were destroyed or damaged; 1,800 people had died, and 3,000 were injured. Local Nazi officials assisted the homeless and tried to incite the residents to hate the Allies. Most residents were fatalistic or passive, and were instead inclined to blame Berlin for their troubles. Thousands fled to villages or farms, but enough stayed behind to keep producing chemicals and to assist troop transports moving by rail to the battle of the Bulge. When draft calls removed German men, I. G. Farben replaced them with German women, with civilian "volunteers" from France or Italy, and with Polish and Russian prisoners. The foreigners worked to avoid death from starvation; the Nazis treated them brutally, and were negligent about their safety during the air raids. Systematic air attacks began in earnest in early 1944, and reduced production by half that year. Repairs took longer and longer, as spare parts were difficult to find. By December, so much damage had been done to vital utilities that output dropped to nearly zero. Followup raids every week ended production permanently.

Interdiction in preparation for the invasion

The third notable achievement of the bombing campaign was the degradation of the German transportation system--its railroads and canals (there was little truck traffic.) In the two months before and after D-Day the American Liberators (B-24), Flying Fortresses and British Lancasters hammered away at the French railroad system. Underground Resistance fighters sabotaged some 350 locomotives and 15,000 freight cars every month. Critical bridges and tunnels were cut by bombing or sabotage. Berlin responded by sending in 60,000 German railway workers, but even they took two or three days to reopen a line after heavy raids on switching yards. The system deteriorated quickly, and it proved incapable of carrying reinforcements and supplies to oppose the Normandy invasion. To that extent the assignment of strategic bombers to the tactical job of interdiction was successful. When Bomber Command hit German cities, it inevitably hit some railroad yards.

The AAF made railroad yards a high priority, and gave considerable attention as well to bridges, moving trains, ferries, and other choke points. The "transportation policy" of targeting the railroad system came in for intense debate among Allied strategists. It was argued that enemy had the densest and best operated railway system in the world, and one with a great deal of slack. The Nazis systematically looted rolling stock from conquered nations, so they always had plenty of locomotives and freight cars.

Furthermore, most traffic was "civilian," and urgent troop train traffic would always get through. The critics exaggerated the resilience of the German system. As wave after wave of bombers blasted away, repairs took longer and longer. Delays became longer and more frustrating. Yes, the troop trains usually got through, but the "civilian" traffic that did not get through comprised food, uniforms, medical equipment, horses, fodder, tanks, fuel, howitzers, flak shells and machine guns for the front lines, and coal, steel, spare parts, subassemblies, and critical components for munitions factories.

1945

On March 1, 1945, infantry from Alexander Patch's Seventh Army ended Ludwigshaven's agony by seizing the city and liberating the slave laborers.

strategic bombing results

The British sent Mosquito bombers over Berlin every night--6,000 sorties in all; their light bombs did little damage but the sirens and rush to shelters ruined every Berliner's sleep.

The most successful bombing was against aircraft, petroleum and transportation.

Besides knocking out the Luftwaffe, the second most striking achievement of the strategic bombing campaign was the destruction of the German oil supply. Oil was essential for U-boats and tanks, while very high quality aviation gasoline was essential for piston planes. Germany had few wells, and depended on imports from Russia (before 1941) and Nazi ally Romania, and on synthetic oil plants that used chemical processes to turn coal into oil. Heedless of the risk of Allied bombing, the Germans had carelessly concentrated 80% of synthetic oil production in just 20 plants. These became a top priority for the AAF and RAF in 1944, and were targets for 210,000 tons of bombs. The oil plants were very hard to hit, but also hard to repair. As graph #1 shows, the bombings dried up the oil supply in the summer of 1944. An extreme oil emergency followed, which grew worse month by month.

Germany's supply of aviation gasoline 1940-45

By January, 1945, the transportation system was cracking in dozens of places, and front-line units had more luck trying to capture Allied weapons than waiting for fresh supplies of their own.