After nearly a decade of developing apps to find dates, hail rides, order pizza, clean laundry, deliver groceries and track your workouts—now Silicon Valley companies are in a race to deliver the flying car.  

The push will deliver a litany of legal and regulatory questions: Who can operate one? How many passengers are allowed inside? Can flying cars fly over roads? What kinds of safety measures must be included, and critically, can the vehicles be manufactured for commercial use?