In 1990, Rockwell Aerospace, North American Aircraft and Deutsche Aerospace built a 7.3 ton X-31 fighter equipped with thrust vectoring (directing engine exhaust flow using vanes and paddles) and a flight control system that could use powerful software to "micromanage" the flight of the aircraft. In theory, this type of aircraft could do maneuvers conventional aircraft cannot. This includes seemingly impossible flying angles and landing on very short airfields. For 13 years, the X-31 developed the ability to perform more and more "impossible" maneuvers. In April, 2003, new software enabled the X-31 to make a fully automated landing at a 24 degree angle. The normal "angle of attack" is 12 degrees, but by doing it at 24 degrees reduces landing speed by 30 percent. The thrust vectoring and control software technology will probably find its way into coming generations of UAVs (unmanned aerial vehicles), especially those designed for combat.