This new propulsion system could rewrite the rules of spaceflight—not to mention completely defy conventional physics.

Zero gravity relies on you, your surroundings, and the air all falling at the same rate, and airplanes flying parabolic arcs ...

The Dornier Do 335’s prototype, powered by twin 1,750 hp Daimler-Benz engines, reached 400 mph at sea level and could still fly 348 mph on a single engine. Standing five meters tall and stretching ...