An eVTOL air taxi is an electric aircraft that takes off and lands vertically, like a helicopter, and carries a few passengers on short flights across a city. eVTOL stands for electric vertical take-off and landing. It has several rotors driven by electric motors, so it needs no runway.
The idea is to avoid road traffic. Imagine a trip from the airport to the city centre, 40 km away. In heavy traffic in Bengaluru, a car can take 90 minutes. An air taxi would fly the same trip in about 20 minutes, from a rooftop landing pad to another. A company founded in Bengaluru is building such an aircraft, with six passenger seats, for India's crowded cities. Its planned production version also carries a fuel tank, so that it can fly farther than on batteries alone.
The landing pads, called vertiports, need space for take-off, a charger for the battery and a place for passengers to board. Between two flights the aircraft must be recharged, so the number of trips in a day depends on how fast the battery charges. The service would have to charge a fare high enough to cover the aircraft, the pilot, the pads and the electricity.
An eVTOL is hard to build for three reasons. First, it runs on batteries. The battery pack and battery management system must hold enough energy for the trip and for a safe reserve. Batteries are heavy, so the range is short. Second, the flight control must be extremely reliable, because many eVTOL designs cannot glide far without power, unlike an airliner. Its avionics handle navigation and flight control, with several backups. Third, a regulator must approve the aircraft before any passenger flies, under safety certification rules. A new type of aircraft takes years to approve.
Some air taxis are planned to fly without a pilot on board. A person on the ground would watch and command the flight from a ground control station, the screen from which an operator plans and watches each flight. Drones already use this approach.
An eVTOL is different from a helicopter. A helicopter uses one large rotor and a fuel engine. An eVTOL uses many small rotors and electric motors, which are quieter and need less maintenance.