Maybe we've been imagining along the wrong model line. http://www.cbc.ca/news/technology/worlds-1st-passenger-drone-unveiled-1.3393437 Still not sure where the fuel would go but I've been using an exchangeable battery in the flying cars in my novel.
Couple this with vacuum balloons and lightweight materials, and it could potentially be efficient enough to work.
I honestly can't see the use for flying cars. Even if they weren't an engineering nightmare, the danger would outweigh any possible benefit. We think drunk drivers are a problem now? Sheesh. Imagine a drunk guy FLYING down Main Street at 90mph. I'm more inclined to think that "car tracks" will exist along the sides of buildings and other vertical surfaces. These would be tunnels that would allow the driver to "drive up" the building or wall or whatever to reach, say, a rooftop parking lot, or maybe to make quick deliveries to people in office skyscrapers and tall apartment buildings. (I can see it now: your office is on the 23th floor, so the pizza delivery boy drives up and meets you at the window lol.)
