“We fly, but we have not ‘conquered’ the air”
— Beryl Markham
Much to the consternation of modern-day strategists, the first generation of aviation specialists were indifferent to academic convention. In the years following the Wright brothers’ first powered flight at Kitty Hawk, bookshelves labelled ‘aeronautics’ were packed with memoirs written by a small band of adventurous young pilots, most of whom would sooner document their personal exploits than hold forth on the potential impact of the aeroplane on the future conduct of warfare. Even after the First World War, little attempt was made to outline a coherent model of airpower. When practitioners did grapple with questions of doctrine and strategy, they tended to focus excessively on pedantic inter-service debates. Early thinking about the military value of aircraft was thus dominated by proselytisers, propagandists, and self-publicists.
Indeed, it was not until the Italian general, Giulio Douhet, turned his formidable intellect to the subject that something approaching a theory of airpower began to take shape. In a series of monographs and articles written during the 1920s, Douhet took aim at the martial axiom, usually attributed to Antoine Henri Jomini¬, that “methods change but principles are unchanging.” On the contrary, Douhet argued, the invention of the aeroplane was a development so profound that it promised to revolutionise the very nature of war itself. Pointing to the bloody stalemate of the trenches, he predicted that the outcome of the next major war would be decided not on land or on sea, but in the air by vast fleets of city-bound strategic bombers. Although Douhet did not live to see the Second World War, in its aftermath many of his admirers were quick to claim that it had vindicated his core ideas.
But was this really the case?
In this essay, I will suggest that the answer to that question is no. Whilst strategic bombing undoubtedly had a bearing on the evolution of the war, its effects were much less impressive than Douhet had envisaged.
The possibility that aircraft might be used to rain down destruction from above had piqued Douhet’s interest as early as 1909. A man with a pronounced scientific-bent and rapacious technical curiosity, the distinctive, modish qualities of the flying machines which had recently begun to appear in the sky naturally appealed to him. Like his Anglo-Saxon contemporaries, though, it was the experience of the Great War which caused Douhet to think and write about this new technology in a sober, methodical, and urgent manner.
In his 1921 book, Command of the Air, Douhet observed that the balance between offence and defence had changed dramatically during the war. On the ground, the combination of mass-production and improved firepower had enhanced the position of the defender whilst simultaneously impairing the position of the attacker. The impasse which this produced was incredibly difficult to break, and, Douhet contended, it was bound to become more acute in the future. In the air, by contrast, the offensive reigned supreme. Since aircraft could travel in any direction, at different altitudes, and at great speeds, they were (a) able to attack targets that were beyond the reach of the army and (b) practically impossible to defend against. “Nothing a man can do on the surface of the earth”, Douhet proclaimed, “can interfere with a plane in flight.” Bearing this in mind, he advocated the creation of an independent air force, consisting primarily of self-defending bomber aircraft. While the army’s new role would be to “resist on the ground”, the nascent air force would act to “create mass in the air.”
But what did this actually mean in practical terms? Or, to be more precise, what were the bombers supposed to do once they were airborne? According to Douhet, the main objective of the air force would be to disrupt and destroy the “vital centres” of the enemy nation—industry, infrastructure, administration, and so on—which had previously been shielded from the excesses of war by obstacles both geographical and social. Though Douhet wrote at length about the expected physical, logistical, and economic consequences of air raids, he was far more interested in their potential psychological effects. Building on Carl von Clausewitz’s observation that an enemy’s “power of resistance can be expressed as the product of two inseparable factors, the total means at his disposal and the strength of his will”, Douhet noted: “aerial offensives can be directed not only against objectives of least physical resistance, but against those of least moral resistance as well.”
If civilian populations were made to suffer the indignities of mass bombardment, Douhet reasoned, they would soon become so fearful of further attacks that they would demand their representatives sue for peace at all costs. Victory would thus go to the side that was able to bomb the opponent’s cities with impunity. Douhet was adamant that this kind of air superiority could only be achieved by obliterating the enemy’s air force whilst it was still on the ground. Any attempt to establish an air defence system was “futile and wasteful, both because it [would be] vulnerable to bomber action and because the end would come too quickly” for it to be useful. For similar reasons, the development of ground-support aircraft was dismissed as a “wasteful, harmful, and superfluous” endeavour.
The extent to which Douhet came to influence the progression of inter-war military doctrine remains a contentious issue. Granted, his name did find its way into countless white papers and field manuals during the 1930s. But as Philip S. Meilinger points out, many of the policymakers who espoused ideas similar to those in Command of the Air had never heard of the book itself. The Royal Air Force (RAF), for instance, adopted what we would now call a ‘Douhetian framework’ well before his work was translated into English. Regardless of where one stands on the issue of paternity, however, it is clear that by the end of the Second World War Douhet’s broad conception of airpower was de rigueur in Europe and the United States. And yet, it was during this conflict that his ideas seemed to clash most violently with observable reality.
Contrary to Douhet’s expectations, it proved to be difficult, if not impossible, to gain control of the skies for a long period of time. Far from being a permanent condition arising from numerical superiority, as Douhet had pictured, the “command of the air” turned out to be something else altogether. It was a fluid, continually contested process that was time-consuming, resource-intensive, and often failed to produce a decisive outcome.
In his rush to paint the aeroplane as the “offensive weapon par excellence”, Douhet failed to keep in mind the old proverb which warns that each improvement to the sword is by necessity accompanied by an enhancement to the shield. Just as the Palliser shot gave rise to compound armour, and the machine gun gave rise to the tank, so the bomber gave rise to integrated air defence. The most important innovation on this front was the development of the monoplane fighter. These aircraft were generally faster and more manoeuvrable than bombers, and many models were equipped with heavy-duty armaments, making them a formidable and imposing adversary. On its own, this advance might have been an erratic nuisance for bomber crews, but when utilised in conjunction with Radio Detection and Ranging (radar) technology and ground-based anti-aircraft guns, it significantly transformed the dynamics of air warfare.
Throughout the war, air defences posed a constant menace to strategic bombers, in most cases preventing them from inflicting the levels of damage that Douhet had thought necessary to compel a nation to surrender. The Battle of Britain, which took place over the late summer and early autumn of 1940, stands as a case in point. In the space of a few short months, the attacking German Luftwaffe recorded a loss of over 1,300 aircraft out of a fleet of 2,550. The RAF, on the other hand, started with a lower baseline number, but managed to keep losses below German levels. In one of history’s great ironies, the first major skirmish fought entirely in the air thus resulted in an “outright victory for the defence.” Even the Allied air campaign over Germany during 1943-1945 failed to achieve the kind of air superiority that Douhet took for granted. Despite enjoying a considerable numerical advantage in terms of both bombers and fighters, the RAF and US Army Air Force (USAAF) regularly suffered exorbitant losses. Whereas Douhet had assumed that an attacking force could lose one-third of its assets on day one and still go onto win the war, in reality “attrition rates of 5 to 10 percent could be serious to the attacker.”
What is more, high-altitude bombing was far less effective than early airpower theorists had prophesised. During the initial stages of the war, the Western Allies conducted a series of major daylight raids on key German cities, but, having met stiff resistance on the ground and in the air, they concluded that such a strategy was unsustainable. After switching to night-time raids, however, defence planners were soon confronted with another problem: given the technology available, it was not possible for airmen to discriminate between different urban objectives, especially since a blackout was in effect across the Reich. The Americans did try to compensate for this by introducing on-board radar systems to their aircraft, but this did little to aid target identification or improve payload delivery. Upon examining data from the twenty-seven radar bombing sorties that the Eighth Air Force carried out in the winter of 1943-1944, operations analysts found that only five percent of the bombs dropped “fell within one mile of the aiming point.”
So, we can say with some certainty that Douhet underestimated the elasticity of defence and overestimated the efficacy of offence. When it came down to it, Clausewitz’s ever-present friction—together with the tendency of human beings to react intellectually and practically to perceived threats—meant that the advent of the aeroplane did not compress space and time in the way that the Italian had hoped.
Still, the British prime minister, Stanley Baldwin, was not far off the mark when he told an anxious House of Commons in 1932 that the “bomber will always get through.” The fleets of aircraft which took to the skies almost daily during the war were considerably larger than Douhet could have imagined, and they ended up dropping more ordnance than he would have thought feasible. And since practical considerations and prevailing circumstances forced most air forces to abandon their experimentation with precision targeting in favour of area bombing, it was civilians who bore the brunt of the air war. The Second World War, then, was an ideal testing ground for Douhet’s ideas about the relationship between strategic bombing, economic privation, and civilian morale—and on the whole, it is fair to say that he would not have been enamoured with the results.
To begin with, there is no evidence to suggest that strategic bombing made a critical contribution to the collapse of war-making capacity in any country. Although there are numerous examples of air raids disrupting production and undermining industrial performance during the war, the damage caused was usually temporary. Even with the best intelligence, the inaccuracy of modern bombers meant that ‘industrial-web’ or ‘bottleneck’ strategies like those espoused by the USAAF were very difficult to implement. With minimal effort, governments were able to disperse production amongst a large number of small factory units, thereby insulating specific industries from precision strikes. At the height of the Allied bombing campaign against Germany, the National Socialist regime did this to great effect. Indeed, German military production continued to increase right up until the first months of 1945. That is not to say that strategic bombing did not cause economic and logistical problems for those nations which found themselves on the wrong end of it. Richard J. Overy observes that “in addition to physical destruction”, affected nations suffered a material “dislocation in the effort devoted to coping with bombing.” Policymakers had no choice but to divert precious resources from the front and the shop floor in order to defend against bombing raids, and this is something that should not be overlooked. The point to stress here, though, is that strategic bombing never threatened to bring a nation’s economy to its knees as Douhet had forecast.
Nor, for that matter, did it cause such panic and fear amongst civilian populations that rebellions and revolutions became commonplace. As Robert Pape convincingly demonstrates in his iconoclastic book, Bombing to Win, Douhet failed to appreciate that (a) conventional munitions are limited in their ability to inflict damage and (b) punishment strategies are often counter-productive. Besides active air defence, states were able to take precautionary measures which reduced their vulnerability to so-called terror bombing. In Britain and Germany, for instance, the government maintained communal air-raid shelters, provided individual households with pre-fabricated shelters, issued the public with gas masks, and organised the evacuation of children from urban areas to the countryside. These are just some of the factors which explain why sustained bombing rarely, if ever, led to serious political instability. By far the most important factor, however, was people’s unwillingness to swap the certainty of immediate hardship for the uncertainty of defeat. As Pape puts it:
“Punishment often generates more public anger against the attacker than against the government. Punishment does produce emotional stress, but this reduces rather than increases collective action against the government, because heavy punishment induces a ‘survival’ response and light punishment, a ‘Pearl Harbour’ effect.”
The Blitz is a good candidate for the latter model: it was relatively short lived; its effects were felt only in a handful of major cities; and it generated a great degree of patriotic feeling and pro-government sentiment across the British social-spectrum. As for the former model, the Japanese experience of 1945 and the German experience of 1943-1945 appear to fit the bill. Both nations were subjected to relentless, intensive bombardment, suffering widespread damage to housing stock and high casualty rates in the process. Yet, in spite of this, neither Germany nor Japan witnessed a catastrophic collapse of morale or an irrevocable decline of political order until the military was on the verge of collapse and the country was on the brink of occupation.
Given all this, it seems evident that Douhet’s efforts to identify the people—or passion, to borrow a concept from Clausewitz’s ‘paradoxical trinity’—as the new ‘centre of gravity’ in warfare were premature. In the end, airpower alone was not enough to compel a settlement. Victory and defeat came about as a result of military, not civilian, vulnerability.
In a sense, Douhet’s biggest mistake was to assume that the second war of the twentieth century would be a repeat of the first. If he had been more attuned to the complexities of the offence-defence balance and more wary of beguiling panaceas, he might have been less likely to put all his eggs in the strategic bombing basket and more likely to recognise the potential of tactical airpower. After all, it was as part of a triad on the battlefield that the aeroplane proved its worth most dramatically. As Bernard Brodie famously remarked:
“Airpower had a mighty vindication in World War II. But it was [Billy] Mitchell’s conception of it—anything that flies—rather than Douhet’s that was vindicated. It was in tactical employment that success was most spectacular and that the air forces won the unqualified respect and admiration of the older services.”
The Germans were particularly vigorous in their use of tactical air assets. During the Battle of France in 1940 and the invasion of Russia in 1941, fighter-bombers operated in combination with tanks and motorised infantry, acting as flying artillery. Having witnessed the success of such close coordination between the ground and the air, the Allies adopted a similar approach during the Western European campaign of 1944-1945. In the Pacific theatre, meanwhile, carrier-based aircraft were used both as forward reconnaissance and as a means of maximising force projection. On occasions in the Far East, tactical airpower was the “component without which the military machine could not be made to work.” At the Battle of the Coral Sea, the Japanese and American fleets did not directly engage one another, but they both suffered heavy losses from air attack.
In an ironic twist, then, the aeroplane helped to restore the kind of mobility to the frontline that Douhet had thought a thing of the past.
Giulio Douhet’s ideas about the utility of airpower were not borne out by the experience of Second World War. Although strategic bombing had a profound influence on the character of the war, it was not decisive for a number of reasons. Firstly, the bomber was not as invulnerable as Douhet had suggested. Together with the crude state of 1940s guidance technology, the development of active air defences during the inter-war years meant that gaining command of the air was a costly and protracted undertaking. Second, the mass bombardment of cities did not produce the kind of economic disruption and political upheaval that Douhet had written about with such confidence. As the bombs fell, industrial production continued and people’s will to resist stiffened. Ultimately, it was tactical airpower—a concept which Douhet had written off—that proved to be the big success story of the war.