History of Aviation

Bomber Theory: Air Power Between Two World Wars

Alf Wilkinson

World War One

World War One saw the emergence of air power in the military field - initially as 'spotter' planes, then as fighters and finally bombers. The Zeppelins were used as 'strategic' bombers in 1915, and extended fighting to the Home Front for the first time. As speed and endurance increased, civilians became more and more in the forefront of war. You can find more detailed account of air power in World War One at The Aerodrome.

After the War

Once World War One ended, strategists were trying to find ways of avoiding the slaughter of the trenches, and re-introducing mobility onto the battlefield. The tank had been one attempt to do this (see Tanks). Other views developed the idea of air power as a way to defeat the enemy. Three people are perhaps best remembered for the new emphasis on air power.

Guilio Douhet's Theory of Air Power

Guilio Douhet was an Italian. He believed that the airplane had completely changed warfare and that airplanes would win wars quickly and decisively. The first priority was to gain command of the air. With command of the air, an air force would be free to operate whenever and wherever it desired. There was, as yet, no effective defence against air attacks. Having achieved command of the air, pilots would then destroy the enemy's will to resist by conducting aerial bombing on his cities, industrial centres and civilian population. It was thought that civilians were not prepared for the effects of war and the bombing of population centres would create panic among the people. People would then pressurize the government to negotiate for peace. Douhet believed the bomber could fight its way to and from the target, hence the origin of the phrase 'the bomber will always get through.' (see Air Power for a further discussion on Douhet's theories).

Sir Basil Henry Liddell Hart

Sir Basil Liddell Hart had fought in the war, and had supported the use and devlopment of tanks. Liddell Hart was also one of the most enthusiastic early supporters of air power. It was the virtually unlimited mobility of the airplane that appealed. The airplane - with its ability to bypass the trenches and strike directly at the heart of the enemy - seemed to offer the best way to quickly win wars. The debates on the proper way to use air power were rapidly coming down in favour of the long-range bomber offensive. A sudden, massive, devastating strike at the enemy's industrial centres seemed the best tactic to destroy his ability to resist.

William Mitchell

William Mitchell was an American. He also believed in the capability of the airplane. In 1930, Mitchell wrote: 'The advent of air power has put a completely new complexion on the old ways of fighting wars. We now realise that the hostile main army in the field is not the main target. Armies themselves can be disregarded by air power if a rapid strike is made against the opposing centres'. So, instead of concentrating air attacks on population centres (as Douhet argues) or the main army, airplanes should be used as strategic weapons to strike deep into the enemy's territory, targeting cities, military related industries and other vital areas. Unlike Douhet's idea of aerial bombing, Mitchell's aim was to be much more accurate and bomb specific targets.

All of these ideas developed because the Generals had not been able to find an effective means of winning the war quickly and cheaply. The idea rapidly spread that air power was the answer. This had two advantages - there was no need for a large (and expensive) army, and, as the bomber would always get through, there was no need to spend money on air defence, as there was no way of stopping a determined attack by enemy bombers. Lots of money was spent between the wars developing bomber fleets.

The Development of RAF Strategic Bombing Doctrine, 1919-1939

When World War Two started, in September 1939, the RAF was unable to deliver the long-promised `knock out blow' against Germany. The optimistic `Air Plans' were shelved, and Bomber Command spent the early months of the war showering German cities with nothing more destructive than leaflets. In its early years, the RAF faced persistent competition from the Navy and Army. To defend its independence, the Air Staff defended the idea that the bomber was a devastating and revolutionary weapon - a different method of waging war, which required a separate air service to wage it. Far too little thought was given to the practicalities of navigation, equipment and bomb-aiming, or to the possibilities of air defence. For example in 1939, despite arguing for twenty years in favour of the strategic air offensive, the Air Staff went to war with little idea about potential economic targets in Germany. It didn't have effective long-range powerful bombers, or accurate navigation aids. Early daylight bombing raids in WW2 were destroyed by German fighter planes, and night raids often failed to get anywhere near their targets. The Bomber Theory was shown up to be a myth. Why therefore had it taken such a hold on Britain's politicians?

The use of the RAF to defeat rebels in the Empire

After World War I Britain had to deal with disorders of all sorts in its empire. Uprisings against British rule, tribal warfare and border problems seemed widespread in the Middle East, Africa, and along India's northwest frontier. The expense of large ground-force expeditions to keep order was seen as a burden. During the early 1920s, the British began to look for alternative ways to control and administer the empire. The Royal Air Force needed to develop methods whereby its aircraft could be used as a cheap, effective force to control the empire.

In the 1920s Britain bombed Kurds and Arabs in Iraq when they rebelled against Britain's attempts to control them. By October 1922 the RAF had principal responsibility for the war, with British ground forces being reduced. In a single aerial sortie, in mid-May 1922, Suleymaniya was bombarded, causing the town's 7,000 residents to evacuate the town for the rest of the conflict. In fact, armed confrontations between Kurdish and Arab nationalists and British imperialism continued until the early 1930s.

Winston Churchill, the colonial secretary at the time, believed that gas could be used effectively against the Kurds and Iraqis (as well as against other peoples in the Empire): 'I do not understand this squeamishness about the use of gas. I am strongly in favour of using poison gas against uncivilised tribes.' Some shared Churchill's enthusiasm for gas as an instrument of colonial control but the British cabinet was reluctant to allow the use of a weapon that had caused such misery and revulsion in the First World War. In the event, gas was used against the Iraqi rebels though gas shells were not dropped from aircraft because of practical difficulties.

Wing-Commander Sir Arthur Harris, later Bomber Harris, head of wartime Bomber Command, was happy to emphasise that 'The Arab and Kurd now know what real bombing means in casualties and damage. Within forty-five minutes a full-size village can be practically wiped out and a third of its inhabitants killed or injured.' It was an easy matter to bomb and machine-gun the tribespeople, because they had no means of defence or retaliation. Iraq and Kurdistan were also used as testing grounds for new weapons; devices specifically developed by the Air Ministry for use against tribal villages.

Hugh Trenchard, the RAF chief of staff concluded "Air power is of vital concern to the Empire and in Iraq, and evidence is growing of its great potential. It may further reduce defence spending, not only in Iraq, but also in other Eastern territories where armed forces are needed to keep control".

Aerial bombardment had proven to be a satisfactory method of mass killing. Jonathan Glancey (The Guardian, 19 April 2003) recalls: "Winston Churchill, secretary of state for war and air, estimated that without the RAF, somewhere between 25,000 British and 80,000 Indian troops would be needed to control Iraq. Reliance on the airforce promised to cut these numbers to just 4,000 and 10,000. Churchill's confidence was soon repaid". Glancey reports that the RAF "flew missions totaling 4,008 hours, dropped 97 tons of bombs and fired 183,861 rounds for the loss of nine men killed, seven wounded and 11 aircraft destroyed behind rebel lines".

You can find out more about the RAF and inter-war operations in the Empire from the following websites: Terror Bombing and Air Power in Small Wars.


During their invasion of Abyssinia in 1935-36 the Italians used poison gas and bombing against the poorly-equipped Abyssinian army and unarmed civilians. It shows how a developed country could use its technology and conquer a foe. Again aircraft played the key role. Without anti-aircraft guns, the Ethiopians could not defend themselves. James Ambrose Brown, wrote: "Abyssinia, primitive and inaccessible in 1935, had been largely conquered from the air. In the campaign Italian air-power had been used with ruthless ability against the massed armies of chieftains and feudal lords. It had attacked the miles-long processions of peasant foot soldiers, mule trains and camp followers, pursued armies broken in battle along the only escape routes, leaving corpses at every river crossing and mountain pass. It had laid waste the land with incendiary bomb and mustard gas. You can find more on the Italian conquest of Abyssinia at the Military History Department.


The bombing and destruction of Guernica in 1937 had an enormous impact on opinion in Britain. Cinemas showed film of the German planes attacking the Basque town as part of the Spanish Civil War. This helped to reinforce the Bomber Theory and the fear of air attack. To find out more about Guernica go to these websites: Spanish Refugees and Guernica.


After Hitler came to power in 1933, Britain had to decide how best to respond to the threat he posed. Britain had a very small army. The Chancellor of Exchequer, Neville Chamberlain, opposed any funding for an army to fight overseas. Chamberlain wanted funding for air power which he considered a more effective deterrent against enemy attack. In the 1930s the theory was developed, as mentioned earlier, that nothing could stop modern bombers. The increased speeds of the bombers reduced the time taken to reach the target, and because they flew higher this made it impossible to send fighters in the air in time to intercept the bomber force. If the bombers were intercepted, their heavy armament would enable them to defeat the attackers. It was a convincing argument, especially because it coincided with the need to save money because of the Great Depression, and the difficulty Governments faced in paying for mass unemployment. This was also the time of the famous 'Peace Ballot' and the Oxford Union debate on not fighting for King and Country. People in Britain felt very strongly that anything was better than another war - and the Bomber Theory suggested that the bomber might prevent another war.

Many military thinkers believed that in any major conflict of the future vast fleets of bombers, pounding the enemy's capital to rubble, would decide the issue in a matter of hours. In 1932 Stanley Baldwin, then a prominent member of the government, gloomily told the House of Commons, 'I think it is well for the man in the street to realise that there is no power on earth that can protect him from being bombed. Whatever people may tell him, the bomber will always get through. The only defence is offence, which means that you have to kill more women and children more quickly than the enemy if you want to save yourself.'

In March 1935 Hitler proclaimed the existence of a new German air force, the Luftwaffe, boasting that it was already equal in size to the RAF. In the late 1930s British air planners anticipated that, if war came, the Luftwaffe would launch an overwhelming air attack on London, referred to as the 'knock-out blow'. It would be swift, sudden and shocking. The Air Staff calculated that the Luftwaffe could deliver 700 tons of bombs a day on London, each ton causing at least fifty casualties. Their heads filled with these doom-laden figures, the Home Office calculated that in the first three months of war 60,000,000 square feet of coffin timber would be required to bury the dead. The proposed expense resulted in the stockpiling of tens of thousands of collapsible papier-mâché and cardboard coffins.

Advised by leading experts, the government also planned for the psychological as well as the physical worst. The Ministry of Health joined the numbers game, estimating that it might have to deal with up to 4 000 000 mental cases in the first six months of war. In these circumstances it was assumed in government circles that civilian morale would crack under air bombardment. Panic-stricken hordes of Londoners would pour out of the shattered capital into the countryside, where the government had plans to turn them back, with machine-gun fire if necessary. People, especially in high places, were scared of the Bomber! For more on this subject see Appeasement and An Appeasement History.


We are used to hearing the arguments about the 'Guilty Men' of Munich, about Appeasement right from 1919 when some thought the Treaty of Versailles too harsh on Germany, about the strong desire not to repeat history and the blood-bath of the First World War. What we don't think about quite so often is the role the Bomber Theory played in all this. Perhaps it was fear of the bomber - as Baldwin said, 'The Bomber will always get through,' that was the driving force behind Appeasement. What do you think?

© , September 1997 - April 2014