(Reuters) -The Federal Aviation Administration on Tuesday finalized comprehensive training and pilot certification rules for flying air taxis, addressing a key hurdle to the deployment of electric vertical takeoff and landing aircraft.

The Federal Aviation Administration has published new rules that it calls “the final piece of the puzzle” toward allowing half-helicopter, half-airplane, electric “air taxis” to start whizzing through the skies.

Powered lift includes aircraft described by industry watchers as electric vertical takeoff and landing, or eVTOL. Using tilt rotors, eVTOL aircraft are designed to take off and land vertically like a helicopter and then transition into forward flight on fixed wings like a plane.