Now, it's released a fantastic 97-page white paper detailing exactly how it wants to integrate electric VTOL multirotor air taxis into its mid-range transport system.

The full document makes fantastic reading for the future-focused. In it Uber leaves no doubt that it believes electric air taxis will be viable, safe and in many cases, both faster and cheaper than cars over a certain distance. Here's a summary of the points we found most interesting.

What will VTOL air taxis look like?

In order to meet the key goals of the Uber Elevate program (safety, efficiency, low cost, minimal noise and disruption, minimal infrastructure) the team has zeroed in on some highly likely design parameters.

Firstly, they'll be electric multirotors, using multiple small rotors instead of a single larger one like a helicopter. This helps keep the noise down (Uber is hoping for around 67 dB at a 250-ft (76-m) altitude, which is around the level of a normal spoken conversation), but multiple rotors also increase stability, ride comfort and redundancy in case of motor failure, not to mention the ability to deal with unbalanced loads like having a passenger on one side and an empty seat on the other.