Now the company has revealed a six-seat air taxi – or perhaps air shuttle is a better way to describe it – called the Y6S Plus.

In the burgeoning ranks of companies working to build electric VTOL aircraft, we haven't seen a propulsion arrangement quite like this before. Autonomous Flight has gone for a tricopter layout, with two large coaxial rotors at the ends of the front canard wings, far enough away that they won't affect airflow over the wings, and a third coaxial rotor mounted at the rear of the aircraft, behind the large main wing.

Tricopters are relatively rare at the small-scale hobby drone end of the market. Here, they offer a weight advantage due to one less arm, motor and prop assembly, but in order to maintain yaw control they need to include a servo motor to tilt the rear prop. The coaxial rotors on the Y6S Plus remove the need for this rotor tilt, but it's still hard to figure out why the designers didn't go for two props at the back and a more traditional quadcopter design. Perhaps to reduce drag in forward flight once the rear props are switched off.

It certainly keeps the look fairly tidy, but one does have to wonder how much stability and control authority it'll allow with only three lift points. The front two rotors tilt forward once the aircraft's off the ground, bringing it to an efficient, winged horizontal flight mode that's good for cruise speeds around 125 mph (200 km/h).