The U.S. military began experimenting with unmanned aircraft as early as World War I. By World War II, unmanned craft could be controlled by radio signals, usually from another aircraft. Vehicles that could return from a mission and be recovered appeared in the late 1950s. Today, unmanned aerial vehicles (UAVs) perform a wide range of missions and are used by all four branches of the military.

https://youtu.be/yC1d4kpaMv4?t=11s