Another early morning jam on the busy radial road to work. Your car has come to a halt amid horns honking from impatient motorists stuck in the ever-extending rush ‘hour’.

Then a message appears, projected onto your windscreen: ‘Do you wish to switch to flight mode?’

You press ‘Yes’, and your car’s battery power switches to four rotors. As your car rises, you escape the congested road below, landing a few minutes later in a vertiport – a car park for flying cars. As usual, you make the office on time.

No wonder the dream of flying cars has existed almost as long as the car itself. An integral part of countless sci-fi films, their take-off always seems to be just a few years away – yet they have failed to