Washington: The bat-winged X-47B is the first autonomous piloted aircraft to land on an aircraft carrier. In terms of its design it resembles a flying saucer from a sci-fi movie.It is developed by US to help the next generation of unmanned aerial vehicles (UAVs).X-47B and its successors are seen as a potential answer to the threat posed by medium-range anti-ship missiles developed by China and Iran.It is sleek and of silver colour. It is capable of travelling at subsonic speeds. As per reports it cost US £1billion.Instead of being piloted by remote control, the X-47B flies autonomously using state-of-the-art GPS navigation technology and flight control software.It is developed by defence company Northrop Grumman, weigh six tonnes and have a range of 2,100miles.It provides the Navy both a long-range strike and reconnaissance capability.The X-47B has raised concerns among some organizations worried about the heavy US reliance on drones in warfare and the rising use of autonomous robots by the American military.The X-47B first flew in 2011, and as of 2013, it is undergoing flight testing, having successfully performed a series of land- and carrier-based demonstrations.A hook attached to the fuselage of the aircraft snags an arrestor cable on deck to bring it to a stop.It weighs six tonnes and have a range of 2,100miles.A report published in Daily Mail earlier this week says senior US naval chiefs have described the ‘miraculous' X-47B as a ‘glimpse of the future.'The X-47B is expected to be in service by 2019.