Delta Air Lines is putting its money where its vision is with a $60 million equity investment in Joby Aviation, a startup maker of an electric aircraft that takes off and lands like a helicopter and flies like an airplane.

Delta is joining United Airlines Holdings and American Airlines Group in investing in the technology with the hope that one day these aircraft will shuttle passengers back and forth to airports above crowded roadways in New York and Los Angeles.

It’s fun to imagine the skies crowded with these aerial taxis flying above snarled vehicle traffic with only a faint hum of rotors as they stream along established routes to and from vertiports strategically stationed on city buildings. This world of George Jetson, however, hinges on some rather large leaps of faith. The biggest of those is whether passengers will eventually be willing to board an aircraft with no pilot on board (the first versions will be piloted).