Autogyros?
Autogyros is where cheap, mass-market aviation is heading. Besides being inherently safe and easy to fly, they can do VSTOL or even VTOL. The fact that they don't have wings makes it much easier to take them on the road. The rotor on the Artur Trendak Zen (formerly Celier Xenon) assembles/disassembles in 20 minutes. Of course, would be nice if it just folded, which isn't far fetched.
Of course, the Zen can't directly drive its tiny wheels for moving on the highway, but if making a roadable aircaft or flying car, I'd surely go this route.