An artist's concept of NASA's first all-electric X-57 Maxwell in its final configuration (Credit: NASA)

NASA's X-plane program, established in 1946 to test and evaluate new technologies and aerodynamic concepts, began with the launch of the X-1 — the first plane to break the sound barrier. Since then, the endeavor has led to numerous industry breakthroughs, including the first supersonic and hypersonic flights, and the first crewed suborbital flight.