Part II : 1950-1957
 The Air Force began planning work to achieve very-high-altitude flight in late 1952 and this resulted in successfully modifying the Martin RB-57, a later version of which is flying today. In 1954 Kelly Johnson of Lockheed, famed airplane designer, proposed a high-altitude reconnaissance airplane that was sponsored by the government. This became the U-2, which is also still flying.
In 1954, Randy Rae proposed a novel hydrogen-fueled subsonic airplane capable of high-altitude flight. Although never built, it spawned considerable interest and activity on the potential of hydrogen as a fuel. The Garrett Corporation acquired Rae's interests and pressed the Air Force for a contract to develop the airplane and its engine, but received only a study contract and some component work. As interest grew and specifications changed from a subsonic to supersonic airplane, the required engine power increased, which meant a much larger hydrogen-fueled engine than Rae originally envisioned. The growth in engine size effectively took Garrett, a maker of small turbines and aircraft components, out of the competition. The government considered it inappropriate to set up Garrett as a manufacturer of large aircraft engines when several capable and well-established companies were willing to do the same thing. Rae and Garrett placed reliance on their patents, and their relationships with the government made a case study of the frustrations of an innovator with a single customer and needing large resources. Some benefits resulted, however; by the end of 1955, interest in using hydrogen in aircraft had grown considerably.