While not as common as in sci-fi of the fifties and sixties you do still sometimes see flying cars in fiction today. The sad fact is that they are not something I think we will ever see in heavy use.
First, whatever was keeping them in the air would have to be way more reliable then modern car’s engine. After all think about how often people run out of gas on the road or have their engine stop without warning, instead of being annoying it could cause a major accident. You would need to have a back up system that would take you from cruising height and speed to the ground safely, this could double the cost of the car.
Second there still would be places your flying car could not go, a large flying hunk of metal would be a major security concern after all. This would limit the usefulness of your flying car.
Third the cars would have to at least share a good amount of information between themselves. This would mean they would be vulnerable to hacking, and that would be really bad. A hacked flying car could cause a lot of damage.
And of course there is the question of if they are needed. The only two situations I can think where they would be really useful would be over very long distances or during really bad traffic. While there certainly are places where traffic is bad, that is not the norm. Even over most of the US they would not get you where your going much faster. Certainly not enough to justify the much higher cost.
Perfect non lethal weapons
What I mean my perfect non lethal weapons is something like phasers set to stun, weapons that can knock someone out with no risk of serious pain or injury.
Even tasers can cause major injuries under the right conditions. They can cause eye injuries, seizures, even collapsed lungs. And of course even if they cause none of these problems directly smacking the pavement when your knocked out is hardly going to be healthy.
The fact is that humans are not made to be turned off easily. Even in a hospital during surgery, under ideal conditions, you have an anesthesiologist. Someone who is there to make sure you stay under just the right amount. Think about that, you have someone who is only to make sure you don’t slip too far under or start to wake up. They would not be there unless it was a hard thing to do.
This leads to the real problem, anything that can knock you out can kill you if used just a little too much. It’s hard to imagine any effect that would knock you out, and do nothing more even after being hit with it again and again.