A “flying car” would be just an aircraft that can fit in a traffic lane. For good reasons, aircraft are regulated much more strictly than cars, requiring regular inspections which are checked, as well as having requirements for flight plans, pre-flight checks and more. Mass-market “flying cars”, if they gained adoption on the same scale as their earthbound precursors, would have to be deregulated much like cars, to the point where Joe Sixpack can drive/fly to the shops on a whim without going through the kinds of pre-flight procedures private-jet-owning multimillionaires pay good money to employ people to take care of for them. Which would mean skies full of poorly maintained rustbuckets piloted by people living paycheck to paycheck who need them to get to their job on time. From time to time, these would fall out of the sky and crush or incinerate people in their homes. If this came to pass, society would have to accept this as the price of progress, in the way it accepts road deaths and mass shootings.