The X47B is a smaller aircraft, at 15 tons, 36 feet long and with a wingspan of 47 feet. It will have a two ton payload and be able to stay in the air for twelve hours.

X45C & X45B combat UAV, Robotic Bombers

U.S. Navy has invested over a billion dollars, so far, in developing combat UAVs (Unmanned Aerial Vehicles) that can operate from aircraft carriers, and replace some of the manned aircraft on carriers