Nearly thirteen thousand B-17 Flying Fortresses—the mainstay of the Allied bombing campaign—were built by Boeing. Yet Congress feared that appropriating funds for such a plane would create fear among the public of cross-oceanic bombing. The start of a goodwill flight to  South America  in February 1938 was designed to allay such fears and promote the plane.

Throughout the war, the Allies were convinced that the Germans were developing, and on the verge of unleashing, super weapons—from jet aircraft to intercontinental rockets to the atom bomb. There was plenty of evidence that could not be dismissed: the Germans had actually deployed V-2 rockets from Peenemunde on the Baltic, and they had all the necessary brainpower in many other areas of science. But what the Allies did not know was that the Germans had a time rule of their own: they did not commit any resources to a weapons project that could not be reasonably expected to yield a field weapon within a year. This rule grew partly out of the belief that the war would not last longer than two years, and partly out of a belief that the industrial capacity of Germany could not sustain a development program for that long.

The Nazis were  right about the second premise, but wrong about the first, and they mistakenly scuttled the programs for the jet aircraft and the atom bomb virtually in the bud. Meanwhile the Allies continued to develop aircraft that could overcome the advantages of the earliest German fighters, as well as long-range bombers that were unchallenged and unmatched by the Luftwaffe. This did not happen easily or automatically: the battles that Billy Mitchell fought and lost had to be waged over again and with greater cunning if an independent U.S. air force was to be created.

As for the Germans, they had learned some lessons from Mitchell and ignored others. Mitchell believed strongly in the development of large, fast, high-flying bombers that were beyond the range of ground fire and faster than fighter aircraft. His first attempt at building such a bomber, designed by Walter Barling in 1919, was an expensive experiment that came to known as “Mitchell’s Folly.” Over the next decade, Glenn Martin provided the Navy with a series of bombers, beginning with the MB-1 that Mitchell had used to sink the Ostfriesland and culminating in the MB-10. The MB-10 and similar fine planes produced in England and France were not going to be adequate if the United States ever found it necessary to fight a war in Europe.

This set Boeing’s chief designer, Clairmont Egtvegt, to work and resulted in the Boeing B- 17 Flying Fortress, arguably the plane most responsible for the defeat of the Germans. In the face of defeatist talk from Lindbergh (who, in fairness, flew combat missions in the Pacific, paid dearly for his isolationist beliefs, and placed his entire knowledge of the German aircraft industry, distilled of German misdirection, at the disposal of General H.H. “Hap” Arnold, chief of the Army Air Corps), aviation pioneer and Russian exile Alexander de Seversky, who had lost a leg flying for the Czar in World War I and was one of the world’s most gifted aircraft designers, encouraged the development of air power and promoted a program that exploited the many weaknesses he saw in the Luftwaffe.

In the final analysis, the air war was won as much by  what the Luftwaffe failed to do as by what the Allies succeeded in doing. The German approach had its roots in the Red Baron’s Flying Circus of World War I) was to provide air support for ground troops in the actual field of battle. The Junkers JU 87 Stuka dive-bombers that descended on Poland in 1939 and were used so effectively as a component of the Blitzkrieg (“lightning war”) were still operating as independent agents in the air, attacking targets with the same kind of spontaneity of the armour and infantry.

This was exactly what made the strategy so effective. But once the lines were drawn, the Germans had no way of maintaining control of the air or extending destruction beyond the immediate battle line. Goring had taken note of Mitchell’s actions at St. Mihiel, but he was unaware of how coordinated an operation it was and how much of his resources Mitchell had devoted to monitoring and directing the planes. The entire practice of dive-bombing was an American invention that World War I ace Ernst Udet witnessed while on tour in the United States and which he brought back with him to his native Germany. The amiable Udet was not a Nazi (he reportedly had a picture of Hitler in his Berlin apartment that he used for target practice) and was not much of an administrator. When he was appointed technical director of the Luftwaffe after Goring took power as Air Minister, many eyebrows were raised.

Ernst Heinkel, one of Germany’s great airplane builders, had several large bombers on the drawing boards; Udet summarily cancelled the program, telling Heinkel that there would be no need for long-range bombers. Analysis of what transpired more than fifty years ago has raised many questions. Udet returned to the United States, now as a high Nazi official, yet the United States encouraged his pursuit of dive-bombing as a technique and even sold him two planes, the Curtiss F8C “Hell-Diver,” which had been developed by the Navy specifically for dive-bombing. By  temperament, Goring was not a man to relinquish glory or power to anyone, least of all Udet, whom he privately regarded as nothing more than a stunt flier. Yet this is what he did, giving Udet all the credit for the Stuka’s success in the invasions of Poland and Norway.

Herman Goering (left: and Ernst Udet, the famed World War I ace who was placed in charge of Luftwaffe development, confer in 1938.