While the USAF has been tacking missiles onto Predator drones for quite some time, so far a true unmanned attack plane has yet to grace any carrier decks -- until now. The US Navy has started flogging an X-47B Unmanned Combat Aircraft System (UCAS) aboard the USS Truman, with a video (below the break) showing it taxiing around the flight deck. The current round of tests has focused on "handling and control characteristics," but officials have said the robotic stealth fighters could be launched from the ship's catapult "if all conditions are nominal." The X-47B has already completed some flight tests, and was even launched from a sling on November 29th, but all that happened at naval air bases, not on the open water. With all the unmanned aircraft coming into the military's system, we can imagine a lot of pilots on the Truman were giving it the stink-eye.