You do realise, that the problem with the flying cars is not building flying cars?
No government will allow you to use it, unless it's way out in the desert...And 20 meters above the ground, like they already doing with the drones.
No one knows and also you are too far ahead. The thing is how? How will you make a flying car? Is it thru magnetism? Do you have the blueprint? This is just the basic things then you can worry later how will you market this and what traffic schemes should government do to adapt and study where these new models will fix the traffic congestion we are having base on the specifications of that "flying car." No government will allow you to use it, unless it's way out in the desert...And 20 meters above the ground, like they already doing with the drones.