A large, classified unmanned aircraft developed by Northrop Grumman is now flying—and it demonstrates a major advance in combining stealth and aerodynamic efficiency. Defense and intelligence officials say the secret unmanned aerial system (UAS), designed for intelligence, surveillance and reconnaissance (ISR) missions, is scheduled to enter production for the U.S. Air Force and could be operational by 2015. (www.aviationweek.com) 更多...