Boeing's Phantom Eye - a liquid hydrogen-powered drone - has set a new prototype endurance record by flying for over five hours during its sixth test flight recently.
The massive unmanned spy plane is designed for long-lasting intelligence and reconnaissance missions at high altitudes.
With the sixth test flight from Edwards Air Force Base in California, the Phantom Eye is designed to eventually be able to fly for up to four days at 65,000 feet (19,800 metres), said a press release issued by Boeing.
At that height, it can spy on enemies, monitor natural disasters and serve as a communications relay.
The plane has a wingspan that stretches 150 feet (46 metres) and can carry up to 450 pounds (204 kg) payload.
The fuselage carries twin fuel tanks, which are filled with liquid hydrogen. Combustion produces only water, making the plane about as green as it can get when it is flying, the release added.
The unmanned aircraft can be outfitted with various intelligence-gathering instruments, including sensors to monitor and track communications.
The Phantom Eye made its first flight above June 1, 2012. But, the inaugural flight ended with a rough touchdown, causing one of the landing gears to break.
