A breakthrough in gasoline production occurred in the United States in 1935 when it became technically possible to produce isooctane with a reading of 100 in large quantities. By 1939, both the American and English air forces had begun to use the improved gasoline, and their planes could then be equipped with correspondingly stronger engines. In Germany, also, a method had been discovered to manufacture such a high-test gasoline, but the process was much more complex, cumbersome, and expensive than the American method, which used different primary materials. Due to these difficulties in production, the Luftwaffe until the end of 1938 neglected to insist on the production of high-octane fuel. For this reason until 1945 the German Air Force had no fuel equal to that available in the English-speaking countries.19
How important the new aviation fuel was is demonstrated by the improved performance it made possible: 15 percent higher speed, a 1500-mile longer range for bombers, and an increased altitude of 10,000 feet. Göring attempted to make amends for the past neglect at the end of 1938 when he demanded that the 19 million barrels of aviation fuel included in the Revised Economic Production Plan be manufactured as high-test gasoline equivalent to the quality of isooctane.2