It isn't even that dramatic.

Statistically close to all trips are within a couple of miles of home. US average vehicle miles traveled per person per day are a staggeringly high 25, yet still, nearly all trips people make are very close to home. Good pedestrian and bike infrastructure is enough to cover virtually all of those trips. You don't need roads for cars. You don't really need trains. You don't need personal aircraft for sure. You don't need autotaxies or any other weird techbro drone solution. You just need maintained, pleasant bikeped routes where you won't feel like at any moment you may get mowed down by a F250 SuperDuty. But we deliberately design spaces to be unpleasant and unsafe for anyone outside of a car to stop people from walking even though designs like that are WAY more expensive for the taxpayer.

High-speed rail and intercity mass transit are super neat and I'd love to see more of it. And that's definitely the kind of trip a "flying car" is primarily confronting. But it's not even the real problem that needs fixing. Trips to a park, grocery store, and bar are the trips that need fixing, and the fact that we encourage and sometimes even force designs where you NEED cars to make those trips is madness.