Billy Mitchell had resigned in February 1926, and died a decade later, in February 1936, having spent the last ten years of his life predicting that the next world war would be an air war, and insisting that the United States should get ready for it. While there were young officers throughout the US Army and US Navy who had heard Mitchell, the upper levels of command were scarcely more willing to believe the premise of his argument than they had been in 1921.
Though his own countrymen had remained deaf to Mitchell’s message, the idea had obviously taken root in Europe, especially in Germany. While the air forces of Europe were expanding during the 1930s, there was no corresponding urgency among the upper echelon leadership of the United States armed forces to do the same. For nearly two centuries, vast oceans had been both physical and psychological barriers which insulated America from foreign wars. Even eighteen years after Billy Mitchell had proven that bombers could sink battleships, the US Navy defense planners still insisted that oceans and battleships were the only line of defense that the United States needed to avoid war. The US Army, meanwhile, still believed that its subsidiary Air Corps existed only to support troops in the field, not to undertake offensive actions behind enemy lines independent of the ground troops.
However, within the Air Corps, Billy Mitchell’s vision for an independent air force capable of decisive action had resonated with many junior officers since the 1920s. By the 1930s, these men were no longer junior officers. One of the leading voices of airpower advocacy within the Air Corps was the officer who became its chief in 1938—General Henry Harley “Hap” Arnold, West Point class of 1907.
Until the early 1930s, the types of aircraft that were being acquired by the Air Corps were principally single-engine trainers and combat aircraft. By the late 1930s, more and more longer range “multi-engine” warplanes were being added to the mix by forward-thinking officers who were rising in the ranks, graduating from bars to oak leaves.
The development of the technology for such aircraft began in 1933, with two secret Air Corps programs that were called Project A and Project D. With this, the seeds of the strategic airpower doctrine, sewn by Billy Mitchell, were germinated. The two secret projects were the first whisper of a breeze in the winds of change blowing into airpower doctrine. The idea in both projects was to examine the feasibility of very large, very long-range bombers.
These projects were significant in that they were conceived as harbingers of aircraft that would be part of a strategic doctrine. Though the United States was being outproduced elsewhere in the world, especially in Germany and the United Kingdom, when it came to combat aircraft, at least the Air Corps was looking ahead in conceptualizing strategic airpower.
Project A and Project D spawned a series of very large aircraft designs, of which the Boeing XB-15 and Douglas XB-19 became one-of-a-kind prototypes. However, the real value of the projects came in the manufacturers, especially Boeing, having developed the technology base for large bombers. This led to the Boeing Model 299.
Designed by a team of brilliant young engineers, notably Edward Curtis Wells, and built at company expense, the Boeing Model 299 first flew on July 28, 1935. At the rollout, Seattle Times reporter Richard Williams described the huge, four-engine bomber as a “flying fortress.” The name was adopted as the official name. In January 1936, after several months of testing, the Air Corps ordered the first Flying Fortresses under the designation Y1B-17, and by 1938, they were ordering small numbers of operational B-17Bs.
During 1939, as Europe went to war, the Luftwaffe took delivery of 8,295 new aircraft, and Britain’s Royal Air Force acquired 7,940. The US Army Air Corps bought 2,141, mainly trainers. In August, they had ordered 38 B-17C Flying Fortresses for delivery in 1940.
In July 1940, with the German armies in control of most of Western Europe, and England seeming to be ripe for the picking, the United States government and military services were faced with the problem of expanding the army and the Navy, and the air services of both. Nevertheless, the acquisition of four-engine bombers still moved at a timid pace. In 1940, the Air Corps would order just 80 B-17C and B-17D aircraft. Among these, 20 were acquired for Britain’s Royal Air Force in the autumn of 1940 under the designation Fortress Mk.I.
The latter is illustrative of how the world viewed four-engine bomber development, and how planners in England had failed to embrace the doctrine of strategic airpower. Even one year into World War II, the Flying Fortress was the only operational four-engine bomber of which significant numbers were in the pipeline.
By this time, the RAF had awakened and the British Air Ministry had ordered the development of aircraft such as the Short Stirling and the Handley Page Halifax, but their operational careers would not be under way until 1941. The Avro Lancaster, considered Britain’s best strategic bomber of the war, would not be in service until 1942.
Meanwhile, a second American four-engine bomber type was coming on line in 1941. Developed by Consolidated Aircraft of San Diego as its Model 32, the aircraft was designated as the B-24 by the Air Corps, and named Liberator. As with the Flying Fortress, some early Liberators were delivered to the RAF in 1941. The first mass-production variant, the B-24D, would make its squadron service debut in the United States the following year.
For all their meticulous planning in terms of aircraft and tactics—not to mention their superior numbers of first-rate aircraft—the Luftwaffe had yet to seriously consider four-engine strategic bombers. Those four-engine aircraft the Germans had developed, such as the Fw 200, were long on range but short on combat durability and payload.
The Luftwaffe had proven itself as an undisputed master of tactical air warfare, but they had failed to develop either the long-range aircraft, or a long-rang plan, for strategic air warfare. Meanwhile, the US Army Air Corps had taken a significant step toward developing the aircraft. Soon it would take a step toward developing a plan.
In June 1941, big changes came to the US Army’s conception of airpower. In a move that would have been unthinkable just a few years earlier, Chief of Staff General George Marshall ordered the creation of an autonomous US Army Air Forces as the operational successor to the Air Corps.
General Arnold, as the commander of the new USAAF, formed an Air Staff and named General Carl Spaatz as its chief. He charged Spaatz, who had already spent time working with the British Air Staff in London, with creating an Air War Plans Division (AWPD). This organization would coordinate with the US Army’s existing War Plans Division (WPD) but would remain independent from it. Headed by Lieutenant Colonel Harold L. “Hal” George, the AWPD came into being in July 1941 and began developing the plan that would be implemented if, or when, the United States became involved in World War II. This plan, known as AWPD-1, would be integrated into the larger joint US Army–US Navy contingency plan known as Rainbow 5.
The cast of young officers who came together around AWPD-1, as part of Hal George’s staff, not only helped draft the plan, but many would go on to play key roles in its implementation. They included Lieutenant Colonel Orvil Anderson, Major Hoyt Vandenberg, and a World War I flight instructor turned businessman, Lieutenant Colonel Malcolm Moss, as well as a pair of West Pointers, Major Laurence Kuter and Major Haywood Hansell. Hansell would go on to command the first B-17 combat wing in Europe, while Vandenberg would command the wartime Ninth Air Force, and go on to serve as chief of staff of the postwar US Air Force.
Ground had yet to be broken for the Pentagon, so these men, among the best and the brightest in the USAAF, rolled up their sleeves and went to work in the Munitions Building on the Washington Mall.
Officially entitled Munitions Requirements of the Army Air Forces to Defeat Our Potential Enemies, AWPD-1 went beyond determining aircraft production goals and developed the comprehensive outlines for a strategy of deploying them to win the war. As Robert Futrell writes in his book, Ideas, Concepts, Doctrine, President Roosevelt himself heartily agreed that the mission of the AWPD was to draft the “requirements required to defeat our potential enemies.”
Completed early in August, AWPD-1 included a strategy for fighting a war not just in Europe, but around the world, from the Western Hemisphere to the Western Pacific. Subsequent AWPD planning, such as AWPD-2 in September 1941, which considered aircraft production, would be based on the general outlines of AWPD-1.
Though Hal George and his team were looking ahead, nobody realized how soon the anticipated American entry into World War II would come.
By the end of November 1941, as an Imperial Japanese Navy carrier group was closing in on the Hawaiian Islands, the USAAF had 3,305 combat aircraft in its inventory. Of these, 145 were Flying Fortresses, and only 11 were Liberators.