If you have a minor prang in your car you can probably ignore it. If you do that in a flying vehicle you should really get it checked over and recertified. Imagine the cost - and the time.

Second problem, imagine the supermarket "vehicle" park if everyone flies in? Or the works car park or shopping mall. Hundreds of people in flying machines all arriving at once with no air traffic control. What could possibly go wrong?

Like many "good ideas," they only seem to work if a small number of people actually take them up.