An ambitious aircraft concept combines the speed of a plane, the agility of a helicopter and the efficiency of a hybrid car Imagine a car veering off a lonely mountain road and tumbling down the embankment. Minutes later, a sleek aircraft zooms in quietly at 230 miles an hour, tilts its wings and rotors up, hovers, and sets down just feet from the wreck. The pilot and a medic load the injured driver into the aircraft and zip back to a hospital at twice the speed of a conventional helicopter ambulance. Simon Scott, the owner of Falx Air, an aviation company based in Staffordshire, England, wants to revolutionize not just medevacs but all personal air transportation. A former communications specialist in the British Army's Air Corps, Scott has been designing Falx Air's hybrid-electric vertical-takeoff-and-landing (VTOL) craft for the past eight years. He's currently bench-testing components in the hopes of getting a single-passenger prototype ready to be certified in January by the...