The US space agency, NASA, has built and flown a remote-controlled plane powered from the ground by the beam of an invisible laser.
During indoor flights conducted in Alabama, the plane flew lap after lap, gliding to a landing once the laser beam was turned off.
While in flight, the laser tracked the 11 ounce plane, striking the photovoltaic cells that powered the tiny motor that turned its propeller.
Scientists envision flying the planes on long-duration flights to monitor the environment, including erupting volcanoes.
