People can barely gas up their SUVs these days. Flying cars will make SUVs look economic by comparison. Seriously, flying cars would have many hurdles to cross to become mainstream: cost, safety, regulation (DMV? NTSB? FAA? All? Good luck with that last one). Most importantly, I don’t think people want flying cars enough to shell out probably 10x the amount they would for a regular car, when you include fuel, insurance, and cost of vehicle.