@ Warm Braw
"there's nothing wrong with the idea of flying cars in principle"
Sorry, there's everything wrong with that idea. First, just look at how people drive in 2D. It's like they can barely handle it. You want those idiots to pilot a flying car ? Why not just shoot yourself right away, it'll hurt less.
Second, there's the problem of getting the vehicle in the air and, more importantly, making 100% sure it doesn't come down before it's supposed to. Airliners have to undergo expensive maintenance at regular intervals, and there's a whole infrastructure around that. Not to mention the certifications of aircraft maintenance technicians. They're not your corner garage mechanic.
Third, there's the issue of breakdowns. Even the best-maintained car will likely be at risk of having something important go haywire. When it happens to a plane, it is generally high enough to be able to navigate to somewhere it can land safely, or it is crashing at the end of the runway. In either case, it is very rare to have a plane crash in a populated area. Flying cars will most likely be flying over cities, where the obstacles are numerous and the population is as well. Any breakdown will most likely result in deaths, most of which will be people who had nothing to do with the flying car - they just got it on the head.
Finally, a flying car has the same fuel issues that rockets have. If you want to go far, you need to store more fuel, which increases weight, which uses more fuel to lift off, thereby diminishing your range. Rinse and repeat to your heart's delight. Pushing something forward is easy, lifting it off the ground without a crane is hard.
But the main argument against flying cars is still the one that just stares you in the face at every commute : the people. They can't spend a minute without checking their bloody phones. That takes their attention off the road. In a flying car, you'll have to be 100% at what you're doing, no exceptions. You don't, you die - and maybe some other people die too.
It's just too much of a risk, on top of being ridiculously non-carbon-friendly..