Flying cars seem to have lots of problems: energy-intensive, loud, and they can fall out of the sky onto other people. Even still, smart people are interested and actively investing in this space.
Sebastian Thrun, CEO of Kitty Hawk (and co-founder Udacity), believes he can solve - or at least mitigate - these problems. Here's an excerpt of an interview between him and Stephen Levy (writing for Backchannel):
Is there any other cranky question I forgot ask?
You could ask about regulators.
Good point. Won’t any level-headed regulator just nix this whole idea?
We are working very actively with the FAA and other regulators, because at the core we share the same concern, which is safety. Especially as you innovate in something that has the potential to put bodily harm or even death to people. It is really important that this is done ethically and safely. As a result we see our friends from the FAA very, very frequently. And we’ve experienced really great collaboration. I am a technologist, so I can invent the technology, but it is the society that has to accept the technology. The more everyone can work together, the better for everyone involved.
Assuming Sebastian's right, then flying cars have at least two big advantages over their land-based analogs: obviously there's more space to fly and thus less congestion, but more importantly, self-flying cars are easier to get right than self-driving cars (fewer obstacles, they don't have to fit with existing infrastructure, and can be instrumented to communicate with other flying vehicles).