Testing immature technology on the general populace is a no-go.
If you know of a way to get a complex system working without real-world testing, then by all means, please enlighten the rest of us.
And what happened to my flying car? They promised me one last century. 
Pick your reason:
1) The pilots' union screamed bloody murder and got it outlawed.
2) People laughed at the people who were trying to make it happen
3) People sabotaged the work of the people who were trying to make it happen
4) What, are you nuts? Have you seen the way people DRIVE? We will get flying cars after self-driving ones, not before. If you want a flying car, get out of the way of the people trying to make self-driving cars work.
(5) We don't yet have, & probably never will, have anti-gravity, which would be the only thing which will make something like the cartoon & SCI-FI "flying cars" work.(The Jetsons one is really a spaceship.)
Everything that has been touted uses rotors or something similar, so that either gives you something like a bubble car, with the real estate requirement of a Hummer, or if it has anything approaching a normal car's seating capacity that of a Helicopter.