Autoguide dug up a recently applied-for patent from Toyota for a crazy-bananas flying car patent in which the wheels have spring-loaded pop-out helicopter rotors. Yeah, we're scratching our heads, too.
Basically, it works like this: You're in your weird future-car driving along, traffic starts to get a little hairy, and you decide its time to take to the skies. You stop, engage flying mode, and the wheels, which are mounted on almost architectural-looking struts, begin to fold upward in a gullwing-like manner. The wheels then sprout rotor blades and spin up, providing lift.
According to the patent filing, the wheels/rotors would likely be electrically powered, though whether that power comes from normal EV batteries or a hydrogen fuel-cell system (like in the Mirai) or some kind of combustion engine isn't exactly clear.
The patent mentions that when in on-land mode, the vehicle could steer in a manner similar to a tracked vehicle (tanks, bulldozers, excavators, etc.) where turning is facilitated by decreasing the speed of the wheels on one side of the vehicle. How effective or efficient that would be when driving in normal city traffic, however, is questionable.
Of course, this is only a patent application, so who knows if Toyota will ever muster up the gumption to build the thing. But with other companies like, and working on flying car concepts, it's certainly more likely now than it would have ever been before.