We've had viable "flying cars" since the 70s. We call them helicopters.

Unfortunately for the futurists, there is a major floor with flying cars, and that's the failure mode. If a car breaks down, it stops. If 2 cars crash, they come to a stop, generally in the road. If a helicopter breaks down, it will have a very bad time, even in the best case. If 2 helicopters crash, then both will almost certainly plummet to their doom, as well as risking those below them.

Because of this, the regulations are a lot stricter on flying cars. This makes them a lot less practical or economically viable. Any other variant will run into the same limitations.