The question of the flying cars points to a key point where reality and fiction breach. Flying cars are of course entirely possible. They’ve been built and tested. The existence of flying cars is therefore entirely feasible. Science Fiction and generations of writers and illustrators going back to Hugo Gernsback were entirely right about that. But technological feasibility and social feasibility are not the same things.
Then consider the nature of the urban environment. Cities crowded with large populations would accordingly be crowded with large amounts of flying cars. Air traffic controllers currently find it tricky dealing with the number of planes currently in the air. The outcome of having hundreds of thousands of flying cars over New York City right where Avery Brooks is standing, is downright inconceivable. For an urban aerial traffic grid of flying cars to be feasible, what is required is a computerized system of traffic control. Singapore has been deploying one and some American cities have begun slowly experimenting with them. At the point that every vehicle can be reliably wired into a central grid and speeds can be carefully controlled, an urban network of flying cars may indeed become possible. In this scenario the reason the flying cars aren’t here is not because of unfeasibility of flying cars, but the unfeasibility of the technology it would take to make them and the environment they operate in, safe.