A prototype of a pilotless fighter jet designed to attack an enemy autonomously and return to base made its first flight on Wednesday, taking a major step toward revolutionising the way battles are fought. Boeing Co’s X-45A aircraft took off from a dry lake bed at Edwards Air Force Base, about 90 miles north of Los Angeles, flew for 14 minutes and then landed back on the lake bed, company and Pentagon officials said. It was controlled by an on-board computer that had been preprogrammed with flight instructions, rather than remotely piloted by a human with a joystick.