Most people will be driving their on cars for some time as it will take a lot of sales to bring down the costs of the flying car's development.
Also it will take people some time to adjust mentally to accepting flying cars. The idea of your engine failing at 5,000 feet is kind of a hurdle for most I think.
But the devil is in the details and as police try to find new sources of revenue for lost traffic fines as so many convert to self driving cars, the few reluctants hanging in there with their manual driving will begin to throw in their towels as they begin to realize that they are the cash cows for the lost fines revenue.