This article was originally published Dec. 1, 2020.
The British armed forces were drawn down and nearly exhausted in 1940. They had survived the Battle of France and—against the odds and expectations—defeated the Germans in the Battle of Britain.
In the doing, however, their losses were so severe that Prime Minister Winston Churchill declared, “We were an almost unarmed people.” Churchill still believed the war could be won because, he told his son Randolph, “I shall drag the United States in.”
The Japanese beat him to it. The United States entered the war following the attack on Pearl Harbor and at Churchill’s urging, agreed to make the conflict in Europe the first priority, ahead of the war in the Pacific.
The Americans wanted to launch a cross-Channel invasion of occupied Europe as soon as possible, but at the insistence of Churchill and the British, concurred in a “Southern strategy” that first challenged the Germans in North Africa, Italy, and through the “soft underbelly of Europe.”
The moment has come when the bombing of German cities simply for the sake of increasing the terror … should be reviewed.British Prime Minister Winston Churchill
Accordingly, until the D-Day landings in 1944, the only significant Allied operations in the West against occupied Europe or the German homeland were the bombing by the U.S. and British air forces.
The official starting date for the Combined Bomber Offensive (CBO) was June 10, 1943, but that is an administrative distinction, based on when certain orders were issued. The offensive must be considered in broader perspective, taking in the first British bombing missions in 1939 and arrival of the first U.S. B-17s in England in July 1942.
The British and Americans disagreed on almost everything about the offensive. The U.S. was committed to high-altitude, daylight precision bombing. The British, having tried that approach and failed, were equally persuaded of wide-area bombing at night.
The Allies backed away early from several targeting sets, including oil and ball bearings, despite good results. Others, such as German submarine pens, were continued for political reasons even though available weapons were not effective.
If the CBO is considered in detail only, it can appear—as various critics have said—that it was not worth the cost or that the Allies, working at cross purposes, were less than successful. Specific objectives were often incompletely met, if they were met at all.
In fact, the dissimilar British and U.S. approaches worked together—although not in the way intended—to divert critical German resources to air defense and to inflict devastation on airfields, cities, industries, and the transportation network. No other factor was of equal importance to bombing in destruction of the German capacity to sustain and continue the war.
The Americans Enter
The main partner of the RAF Bomber Command in the Combined Bomber Offensive was U.S. 8th Air Force. Brig. Gen. Ira C. Eaker led an advance echelon to England in May 1942, followed by the commander, Maj. Gen. Carl A. Spaatz, in June.
The British expected the newcomers to join in the ongoing bomber program and to accept the leadership and experienced judgments of the British. That did not set well with the Americans, but for the time being, they deferred considerably to the British. As their share of the forces and funding increased, though, so did their independence of action.
The B-17s did not fly their first mission until Aug. 17. Three days later, half of 8th Air Force’s manpower and 1,100 of its airplanes were taken away and ordered to North Africa, where they formed the new 12th Air Force to implement the Southern strategy. Spaatz also went to Africa as part of the package.
Eaker, who took command of 8th Air Force, was left with only about 150 heavy bombers. It was no surprise that the results were meager. In January 1943, Eaker said, “We are bombing Germany now with less than a hundred heavies.” Not until May was Eaker able to put missions of 150 bombers into the air.
Eighth Air Force had some B-24 Liberators but was associated mainly with the B-17 Flying Fortress, which dropped more bombs than any other U.S. aircraft in World War II.
The biggest issue dividing 8th Air Force and Bomber Command was precision versus area targeting. The British began strategic missions against Germany in September 1939 with their own presumption of precision attack, but it did not go well. On average, only a third of the bombs hit within five miles of the aiming point. In the Ruhr Valley—Germany’s industrial heartland, defended by guns and fighters—strikes were even less accurate.
In late 1941, the RAF broke off the attempt at precision bombing and in February 1942, the British Defence Committee ordered a switch to night area bombing, principally against urban centers.
In their public announcements, the British said that any harm to German civilians was corollary, not deliberate. “The targets of Bomber Command are always military but the night bombing of military objectives necessarily involves bombing the area in which they are situated,” said Air Minister Sir Archibald Sinclair.
Among themselves, British leaders acknowledged a different objective. The so-called “de-housing” paper, sent to Churchill from his scientific adviser, Lord Cherwell (Frederick A. Lindemann), in March 1942, said that if heavy bomber missions were sent against 58 large German cities. “The great majority of their inhabitants (about one-third of the German population) would be turned out of house and home. … There seems to be little doubt that this would break the spirit of the people.”
Air Chief Marshal Sir Charles Portal, chief of the Air Staff, supported that goal. With a strong effort, he said, 6 million German homes could be destroyed and 25 million Germans made homeless.
“From beginning to the end of the war, ministers prevaricated—indeed, lied flatly, again and again—about the nature of the bomber offensive,” said British historian Max Hastings in his authoritative book, “Bomber Command.”
Churchill’s fingerprints are difficult to find on the de-housing policy. However, he said that “as the war went on, we hoped to shatter almost every dwelling in almost every German city.” After the attack on Dresden in 1945, he said that “It seems to me that the moment has come when the question of bombing of German cities simply for the sake of increasing the terror, though under other pretexts, should be reviewed.” (Emphasis added.)
Air Marshal Arthur T. “Bomber” Harris took over Bomber Command in February 1942, a week after the Cabinet directive on area bombing. Although the policy did not originate with him, he became the leading advocate of it. He opposed allocation of Bomber Command aircraft to what he called “panacea targets,” such as oil plants and aircraft factories. He did not believe Cherwell’s notions about de-housing and German morale. His conviction, pure and simple, was that area targeting got the best strategic results.
In 1942, the big, four-engine Lancaster entered service with Bomber Command and became the definitive British bomber of World War II. It was well-suited to area targeting, carrying a regular bomb load of 14,000 pounds, more than twice that of a B-17.
“Although spasmodic precision attacks would take place for the rest of the war, of the total tonnage of bombs dropped by Bomber Command throughout its campaign, three-quarters were directed against urban targets,” historian Hastings said. Whatever its effectiveness on industrial infrastructure, area bombing did not eviscerate German morale as predicted.
The popular claim before the war was that U.S. bombardiers, using the acclaimed Norden bombsight, could put a bomb in a pickle barrel from high altitude. “We do not regard a 15-foot square as being a particularly difficult target from 30,000 feet,” said Ted Barth, president of the company that made the bombsight.
That was stretching it considerably, although results from in training and exercises were good. Accuracy was measured by the “circular error probable (CEP),” the radius of a circle in which at least 50 percent of the bombs landed.
In 1939, the average CEP was 254 feet from an altitude of 1,500 feet. However, 97 percent of the total bombs were dropped from lower than that, and aircrews routinely got even better CEP scores on low-level bomb runs.
Precision attack in combat was a different matter. Enemy air defenses forced the B-17s to fly at higher altitudes. Holding to a leisurely, straight-and-level course, led to great risk. Aiming points were obstructed by clouds, smoke, and debris.
“Rather than dropping bombs into pickle barrels, 8th Air Force bombardiers were having trouble hitting the broad side of a barn,” said historian Stephen L. McFarland of Air University. Average CEP soared to 1,200 feet.
Not all of the strikes were wild misses, though. By definition, half of the bombs fell inside the circumference of the CEP. Some of them were direct hits. The price for this achievement was a high loss rate for daylight precision bombers. CEP eventually improved when P-51 and P-38 escort fighters came into service to establish air superiority and give the B-17s a better chance on the bomb run.
Churchill had President Franklin D. Roosevelt almost convinced that the B-17s should join Bomber Command in operating at night. Before that happened, Churchill met with Eaker during the Allied conference at Casablanca, Morocco, in January 1943, and Eaker talked him out of the idea. His key point was the value of keeping the Germans under attack both day and night.
The Casablanca Conference called for the Combined Bomber Offensive, which officially began June 10 by order of the Combined Chiefs of Staff. They approved both area and precision operations and assigned four specific target sets: submarine construction yards, the aircraft industry, transportation, and oil plants.
“Army Air Forces remained committed to daylight precision bombing until the end,” historian McFarland said. “American Airmen intentionally aimed fewer than 4 percent of their bombs at German civilians.”
“The division of the Combined Bomber Offensive prevented the Americans from playing any part at all in the strategic offensive against Germany in the course of 1942,” sniffed Noble Frankland, director of the Imperial War Museum in London. “Nor did it result in any worthwhile contribution from the distinctively American offensive in the course of 1943.”
Responding to Frankland, USAF historian Robert Frank Futrell said, “The essential problem in this period was that the 8th Air Force was too small,” and “the targets handed down to it (especially the almost invulnerable submarine pens) were little calculated to accomplish any great decision.”
In special situations, the British—except for the stubbornly resolute Bomber Harris—were in favor of attacking precision targets. The prime example was the hardened submarine pens on the French coast.
German submarines were regarded by both the British admirals and public opinion as a compelling threat and they had to be struck, even though they were defended by German fighters and conventional bombs had no effect on them.
In the first quarter of 1943, fully 63 percent of the 8th Air Force missions and 30 percent of the RAF missions were against the submarine pens.
“Wave after wave of heavy bombers all but obliterated the French ports of Lorient and Brest where the German submarine pens were based, without once inflicting serious damage on the reinforced concrete structures that protected the U-boats,” said British historian Richard Overy.
Likewise, both British and American heavy bombers were diverted to V-1 Vengeance weapon sites when German “buzz bombs” began falling on London in 1944. U.S. bombers and fighters flew 44,702 missions against the V-weapon sites, and the British flew 24,211.
For one reason or another—the aircraft loss rate, gaps in intelligence information, or the objections of naysayers—the Combined Bomber Offensive more than once failed to follow up on initiatives that had shown promise.
In the famous “Dambusters” raid of May 1942, RAF Lancasters destroyed two large hydroelectric dams—among the largest man-made structures in the world—in northwest Germany. Each bomber carried an experimental four-and-a-half-ton bomb. When the reservoirs collapsed, they sent millions of cubic feet of water rushing down the industrial Ruhr Valley in a tidal wave sometimes 40 feet high.
It demolished every road and rail bridge for 30 miles and the damage extended for 100 miles. Factories, buildings, and war materiel stockpiles were destroyed and production was disrupted. It took the Germans months to rebuild the critical infrastructure, but the British did not strike again, even when the wooden scaffolding around the construction presented an easy target. Harris was unwilling to commit any more Bomber Command aircraft for non-area purposes.
“That night, employing just a few bombers, the British came close to a success that would have been greater than anything they had achieved hitherto with a commitment of thousands of bombers,” said Albert Speer, the German armaments minister.
The oil supply was an obvious choke point. Germany had almost no petroleum resources of its own and depended on foreign supply. A third of its aviation and diesel fuels came from Ploesti in southern Romania. That was too far for B-17s to reach from England, but in range for B-24s, which mounted a strike in August 1943 from Benghazi in Libya.
The battle plan fell apart. The B-24 formation became separated in flight, approached Ploesti from three different directions, and the attack was badly disjointed. Nevertheless, the raid knocked out 46 percent of Ploesti’s oil production. Given the high bomber losses and poor execution of the raid, there was no support for more oil strikes despite the extraordinary success against the fuel plants and refineries at Ploesti.
According to Speer, the ball bearing facilities at Schweinfurt in Bavaria “were crucial to our whole effort.” The aviation industry alone used 2.4 million ball bearings a month. Half a dozen plants in Schweinfurt produced almost two-thirds of the total supply.
B-17s bombed Schweinfurt twice, in August and October 1943, and destroyed 67 percent of the ball bearing production. However, almost 20 percent of the attacking bombers were lost, which led British historian Noble Frankland to declare that “America’s ‘Waterloo’ was at Schweinfurt in October 1943.”
It looked different from Speer’s perspective, especially when the bombers did not come again. “The Allies threw away success when it was already in their hands,” he said. The Germans scraped by, meeting their needs from existing inventory and the production capacity that remained. As soon as bearings came off the line, they were picked up by porters and carried in backpacks to assembly points.
The Offensive in Full
As preparations began for the D-Day invasion, Spaatz, now a three-star general, returned to England in January 1944 as commander of U.S. Strategic Air Forces in Europe. Maj. Gen. Jimmy Doolittle came along as 8th Air Force commander. Eaker took command of Mediterranean Allied Air Forces.
The shortage of B-17s ended abruptly. Whereas Eaker had struggled to put several hundred aircraft together for missions in 1943, Doolittle launched a force of 660 heavy bombers within a week of taking command. Between September 1943 and May 1944, bomber strength increased from 461 to 1,655.
Doolittle concentrated his attack on the Luftwaffe, in the air and on the ground. The Germans were able to maintain aircraft production for a while by mobilizing parts of industry not mobilized before and dispersing from 27 main plants to 729 smaller ones.
Fighter output declined in the last half of the year, but the larger problem for the Luftwaffe was that Spaatz made the synthetic oil industry a high-priority target. The supply of aviation fuel dropped from 175,000 tons in April to 5,000 tons in September. German fighters sat idle on the ramp.
The combination of British and American attacks of various kinds left the Germans no choice but to set up a massive air defense network.
“The barrels of 10,000 guns were pointed toward the sky,” Speer said. “The same guns could have been employed in Russia against tanks and other ground targets. Had it not been for this new front, the air front over Germany, our defensive strength against tanks would have been more than doubled as far as equipment was concerned.”
“Seventy-five percent of all German 88s (their best artillery piece and also best tank killer), were being used as antiaircraft guns,” said Phil Meilinger, former dean of the School of Advanced Airpower Studies. “The aluminum used to make AAA (antiaircraft artillery) shells was enough to have built an additional 40,000 airplanes.”
“Allied air power was decisive in the war in Western Europe,” the U.S. Strategic Bombing Survey (USSBS) said. That claimed too much. The land, sea, and air components all had a share in the credit. However, the USSBS point cannot be dismissed altogether.
Berlin fell to the Soviet army May 2, 1945, and surrendered May 7. In the 10-month ground offensive in Western Europe, the British and American armies had advanced from Normandy to the Elbe, where they had stopped, 65 miles from Berlin. They did not attempt to capture the city since it had been decided already that Berlin would be well inside the postwar Soviet occupation zone.
“Without the Combined Bomber Offensive, it does not take a rocket scientist to figure out that an additional half-a-million soldiers and 10,000 high-velocity guns on the Eastern Front might have had a disastrous impact on the Red Army’s ability to fight the war in the East,” said U.S. historian Williamson Murray.
Speer told Eaker after the war that “without this great drain on our manpower, logistics, and weapons” as a result of the bomber offensive, “we might well have knocked Russia out of the war before your invasion of France.”
The event generating the most disapproval of the Combined Bomber Campaign was the bombing of Dresden by British Lancasters and U.S. B-17s in February 1945. The moral outcry it raised continues many years later.
Dresden, an old and graceful German city on the banks of the Elbe had considerable history and charm, but it was also a major transportation hub through which the Germans could reinforce the Eastern Front and counter a new Russian offensive that was driving toward Berlin.
British intelligence warned that the Germans might be about to reposition 42 divisions from France, Italy, and elsewhere to the Eastern Front. The Russians asked the Allies to bomb the key transportation juncture at Dresden.
“Two waves of Royal Air Force firebomb attacks and a follow-up U.S. Army Air Forces raid all but obliterated Dresden,” Rebecca Grant said in a report for Air Force Magazine. “Huge incendiary assaults created a firestorm that consumed everything in its path.”
Critics, mostly in the postwar period, depict Dresden as a war crime, not a legitimate military target, and coming too late in the war to make a difference.
When the United States finally turned its attention to the Pacific, there were not that many large military industrial sites in Japan. Accordingly, the B-29s of 20th Air Force employed incendiary bombs in area bombing of Japanese cities.
That, however, was not the case with the two decisive B-29 missions that induced the Japanese surrender by the use of the atomic bombs. Both of them were classic daytime high-altitude, precision bombing attacks.
On Aug 5, 1945, Maj. Thomas Ferebee, the bombardier on the Enola Gay, used the Norden bombsight linked to the Honeywell C-1 autopilot, to find his aimpoint, a T-shaped bridge in Hiroshima. He obtained the target from 10 miles out at 30,700 feet and the bomb detonated 800 feet from the bridge. On Aug. 9, the Bockscar bombardier, Capt. Kermit K. Beahan, released his weapon from 31,000 feet. It hit 1,500 feet from the aimpoint in Nagasaki.