“It is probable that future war will be conducted by a special class, the air force, as it was by the armored knights of the Middle Ages.” BRIGADIER GENERAL WILLIAM “BILLY” MITCHELL WINGED DEFENSE, 1924.
By 1918 there was a solid weight of opinion in the Allied countries calling for a bombing offensive against Germany, and frustration among political leaders at the military’s failure to deliver it. In April 1918, Britain created the world’s first independent air force, the Royal Air Force, to replace the army’s Royal Flying Corps and the navy’s Royal Naval Air Service. It was intended, among other things, to help give Britain more effective air defences, and to promote a strategic air offensive against Germany. The Independent Force of bombers was set up in June to carry out this offensive. Meanwhile the French commander-in-chief, Marshal Henri Pétain, called for a fleet of heavy bombers to “paralyze the economic life of Germany and its war industries by methodical and repeated action against principal industrial cities…”. In 1918 the Allies had the de Havilland-designed Airco D.H.9 and excellent Breguet Br.14 as day bombers and the Handley Page O/400 and Caproni biplanes and triplanes as night bombers. The Handley Page, although nothing like as big as the German R-planes, could carry a maximum bombload of 900kg (2,000lb), and formed the backbone of the Independent Force. Other heavy bombers, including the French Farman Goliath and the British Vickers Vimy, were under construction in 1918 but arrived too late to see service.
In the summer and autumn of 1918, formations of up to 40 Allied bombers flew raids deep into Germany. Predictably, bad weather and unreliable aircraft limited the effectiveness of the bomber offensive. But civilians in cities such as Frankfurt and Mannheim were taught the terror of air-raids that had already been experienced by inhabitants of Paris and London. Allied airmen were always under orders to aim for precise targets, such as factories or communications centres. But Allied political leaders were keen to affect civilian morale. The British Secretary of State for air, William Weir, told Hugh Trenchard, the commander of the Independent Force, not to be scrupulous in respect for civilian life: “If I were you,” he wrote, “I would not be too exacting as regards accuracy in bombing railway stations in the middle of towns. The German is susceptible to bloodiness, and I would not mind a few accidents due to inaccuracy.”
In fact, the air commanders were generally more sceptical about strategic bombing than the politicians. Trenchard knew he was supposed to use his force to bomb German cities and factories, but more often he directed it against tactical objectives such as airfields and communications centres behind the front. The same is true of US General Billy Mitchell. Both Trenchard and Mitchell later became advocates of strategic bombing, but they devoted themselves in the last months of the war to the tactical use of airpower.
The evidence of World War I was that, at current levels of technology, strategic bombing could neither seriously disrupt industrial production nor significantly weaken a population’s will to fight. Bombing was costly and inaccurate. Its chief positive effect lay in forcing the enemy to divert resources to air defence.
The building and operation of large bomber aircraft was nonetheless an important step in the progress of aviation. Bomber aircrews had accumulated extensive experience of long-distance flight and night flying, and the large aircraft they flew carrying bombs could, with relatively small modifications, carry passengers or freight instead. Strategic bombing in the Great War helped pave the way for the development of commercial aviation – as well as the devastation of Dresden, Tokyo, and Hiroshima.