The origins of the Dyna-Soar program can be traced to concepts advocated by the German scientist Eugen Sänger as far back as the early 1930s, when he first proposed the development of boost-glide hypersonic aircraft. Sänger envisioned spaceflight as the next logical development in aviation, and he continued his design studies for a winged hypersonic vehicle for the remainder of the decade. The studies of Sänger and his fellow scientist (and future wife) Irene Bredt caught the attention of German military authorities, but the outbreak of World War II forced the Germans to focus their available resources on proven, rather than hypothetical, weapon systems.
As the war continued, desperation forced German military authorities to reconsider Sänger's ideas with the hope of developing a breakthrough weapon that might turn the war in Germany's favor. At one point, Sänger proposed to the German high command that a skip-glide plane capable of bombing New York City be built. Launched into a suborbital trajectory, the plane would have "skipped" along Earth's atmosphere, dropped its four-ton bomb load on New York, and glided back to its launch site in a series of decreasing bounces. Fortunately for the Allies, there was not enough money, resources, or time to construct the Sänger-Bredt "Silverbird." When American scientists obtained access to Sänger's research after the end of World War II, many of them became aware for the first time of the real possibility of creating a space plane that could function much like a conventional aircraft in outer space. As knowledge of Sänger's work spread through the U.S. military, many Air Force planners came to believe that the outcome of the next major conflict might well be decided in the near-Earth or space environment.