The Strategic Bombing Campaign

In the beginning...

The first powered flight was made by the Wright Brothers in December of 1903, but it was in Europe that the military use of aircraft was advanced especially during the First World War. The United States entered that conflict in 1917, relying mainly on the British and French for combat aircraft.

The Royal Air Force, the world’s first independent air force, was created in 1918. American military airmen sought similar autonomy during the years after the First World War, but this was resisted by the traditionalist US Army and US Navy. Those who believed air power worthy of an independent role saw strategic bombing as the doctrine to achieve this objective.

The US adopted an isolationist policy but while military aviation was neglected the vast distances separating American cities spurred the development of civilian aircraft. By 1939 the most advanced air transports were those built in America, the airframe and aero-engine technology they achieved could be applied to military aircraft.

The Second World War

The outbreak of war in Europe in September 1939 led both Britain and France to finance the expansion of the US aircraft industry to supplement their own production. Realising the probability that America would eventually become involved in the war, the US government began to fund expansion of its air arms.

The apparent success of the bomber, first in Spain and China in the late 1930s and then in the Nazi Blitzkrieg of spring 1940, finally persuaded the US government to back the Army Air Corps’ doctrine of high-altitude, daylight precision bombing. This had been developed around the Boeing B-17 Flying Fortress, the world’s first all-metal four-engine bomber.

The USAAF plan

Despite the RAF’s high losses in daylight bombing operations, also experienced by the Luftwaffe during the Battle of Britain, the Americans thought they could succeed where others failed.

The British and Germans had conducted operations at an optimum ten thousand feet, but higher flight was restricted by the thin air at those altitudes. The Americans planned to operate around twenty-five thousand feet in the sub-stratosphere which they believed would be beyond the range of both anti-aircraft artillery and enemy interceptors. To go to this height they developed a self-regulating oxygen system for crewmen, engine turbo-supercharges and a precision bomb sight, the Norden. High altitude flight was a rarity in the early days of the Second World War - pressurised cabins and turbojets were still in the future.

From December 1941, the United States was at war with the Axis powers and the Allies agreed to seek defeat of Germany first. The way was open for the US Army Air Forces to conduct operations from Britain.

Though still part of the US Army the USAAF had become semi-autonomous. However, its leaders still sought greater independence.  Bombers used as an offensive force in their own right were seen as a means of achieving this. They believed that a strategic bombing campaign aimed at destroying the enemy’s war making potential could fatally weaken the enemy and lead to victory. With this aim, the USAAF activated its first offensive air force, the 8th Air Force, to operate from Britain.

The Mighty Eighth

The Eighth became the main realisation of the plan for strategic warfare through daylight, high-altitude precision bombing. In terms of men and machines, it grew to become the largest air striking force ever committed to battle, able to launch three thousand bombers and fighters on a single day’s operations.

The Eighth’s strategic bombing campaign began in August 1942, and the operational technique pioneered during the next few months remained little changed to the end of the war.

After take-off from their East Anglian bases the B-17 Fortresses and B-24 Liberators assembled in group formations of twenty to forty aircraft before proceeding out at high altitude towards enemy territory. These large, close formations had massive defensive firepower, which some thought would be enough to protect them from German fighters.

By placing the most experienced crews in the leading aircraft, and by having all the aircraft release their bombs on the leader’s aim, they achieved a concentrated pattern of strikes on the target.

During the first year of these operations the B-17s and the B-24s had only short range fighter escort. As the American bombers forged further into the enemy’s airspace so the Luftwaffe fighter opposition mounted, taking an increasing toll.

Some of the fiercest and most prolonged air battles of the war took place during these daylight raids, with high claims of aircraft shot down on both sides. The Eighth Air Force bombers suffered very heavy losses.

It was clear that if the day bomber campaign was not to founder, long-range fighter escort was vital.

The Combined Bomber Offensive

Early in 1943 the Eighth joined with RAF Bomber Command in a Combined Bomber Offensive. Its aim was to be:

‘…the progressive destruction and dislocation of the German military, industrial and economic systems and the undermining of the morale of the German people to a point where their capacity for armed resistance is fatally weakened.’

This allowed both the RAF and the USAAF to pursue their own policies to achieve this aim – the RAF focusing on ‘area bombing’ German cities at night, and the USAAF attacking targets during the day.

It was also agreed that the destruction of the German aviation industry was a leading priority. Other specific areas of the German war machine were to be targeted as the campaign unfolded.

A large obstacle to effective, accurate bombing was the poor weather in north-west Europe, especially in winter. High altitude precision bombing required clear skies but operations were frequently frustrated by the weather.  This led the Eighth to adopt and develop British radar devices for bombing through clouds. As the American crews discovered, precision attacks against specific military or industrial targets were extremely difficult, even in daylight.

Protecting the bombers

The P-47 Thunderbolts supported the bomber missions during the summer and autumn of 1943, their radius of action extended from 200 miles to 350 miles by externally carried ‘droppable’ fuel tanks.  The development of these pressurised ‘drop tanks’, most of them made in Britain, was very important in the battle with the Luftwaffe.

The P-47 was twice the size and weight of a Spitfire, it had a slow rate of climb and sluggish acceleration but it could easily overtake the enemy fighters in a dive and had tremendous firepower.  From the autumn of 1943 the P-47 groups began to employ very successful tactics.

The P-47s were joined by P-38 Lightnings in efforts to protect the bombers but the Lightning, though giving valuable aid, was beset with technical troubles.

Air superiority

The fighter that saved the day for the Eighth’s bombers was the P-51 Mustang with the US-built version of the Rolls-Royce Merlin engine.  The Mustang’s performance was superior to the enemy fighters in most respects and it had built-in tankage which gave a 350 mile radius of action.  With drop tanks it could provide support for the bombers to their most distant targets.

The first Merlin-engined P-51s went into action in December of 1943 but it was not until three months later that substantial numbers were on hand.  By this time the Luftwaffe fighters had become the hunted rather than the hunters.  By May 1944 the American long-range fighters had secured air superiority over most of western Europe, a situation not thought possible only a few months earlier.

As well as overcoming the Luftwaffe in the air, from early 1944 the US fighters were encouraged to attack enemy aircraft on their airfields whenever opportunity allowed.  In fact, the Eighth Air Force began to use its fighters for offensive operations, strafing other ground targets such as rail, road and water-borne traffic.


With the Luftwaffe neutralised the strategic bombers turned their attention to the enemy’s oil supplies. By the autumn of 1944 the Third Reich faced a critical crisis over petroleum products: the German oil industry had been virtually destroyed by bombing.

The birth of the Ninth

In autumn of 1943 one of the Eighth Air Force commands was taken to form the new 9th Air Force to support the ground forces during the invasion of continental Europe. The Ninth was built up to equal the Eighth in numbers of personnel and aircraft. As well as a thousand fighter-bombers and tactical reconnaissance aircraft it had two hundred A-20 Havoc and five hundred B-26 Marauder medium bombers, and the largest force of transports in the world, a thousand C-47s.  After D-Day the Ninth moved over to France and supported the advancing armies as they moved through Europe.

The results

By the end of the war in May 1945, Germany’s cities lay in ruins. The cost in human terms was high; over 80,000 Allied airmen and around three quarters of a million German civilians lost their lives. In the years following the Second World War historians argued about the morality of a campaign in which so many civilians were killed.

But although the strategic air offensive did not alone win the war, as some of its exponents had hoped, it did help the Allies defeat Nazi Germany. It restricted the development of German industry. It kept over one million men and 55,000 guns away from the front line defending German cities. It helped win the Allies control of the skies over Europe, enabling the launch of D-Day and the campaigns that followed. Albert Speer, German armaments minister, called it ‘the greatest lost battle on the German side’.


Find out more about the missions undertaken by the Eighth Air Force in the Strategic Bombing Campaign.