Flying cars? With propellers for wheels? Isn't that extremely loud? Don't they need much more fuel than normal cars? And what breaking distance does a flying car have? How many children's heads are chopped off? Are skyscraper windows flying car safe? And so forth. Seriously, flying cars is one of the most unfeasible ideas out there.
Flying cars would be more sensible with some anti-gravity magic, and when they can instantly stop. And stuff.
Allow me to be clear: In my view, 2- and 4-seater airplanes
are essentially flying cars. They already exist and are in common use, just not by many people. Adding a highway capability is just sealing the definition.
Some people won't accept "flying cars" until they have VTOL and any old high school student can operate them after 10 minutes practice in a parking lot, but that's not the definition I'm using.
Fuel consumption for a plane is measured in gallons per hour rather than miles per gallon, but assuming calm winds, a comparison can be made. It's true plane fuel economy is lagging behind cars, but it isn't so terrible. Consider a Cessna 172 travelling at 110 knots (typical cruise). It will burn around 8GPH, and in an hour will travel 110 nautical miles (about 126 statute miles). This is an effective efficiency of 16 MPG. It's possible to lean the mixture at altitude to increase that.
As far as skyscrapers go, a year or two ago someone intentionally crashed a Piper into an IRS building. The plane was destroyed, but the only damage to the
building was the (empty) office it struck. Small planes simply don't have enough mass or fuel to be all that much of a hazard. A bus would make a better terrorist weapon.
Although modern planes are very safe, I don't think they will ever be as safe as cars can be in the hands of an ordinary driver. Most car accidents are not fatal, and if your car runs out of fuel or otherwise fails, it's usually just going to roll to a stop (and you can most likely brake your way to a stop, too.) Obviously, there are more extreme circumstances (like a wheel coming off) but most mechanical failures in cars don't carry a high risk of injury/death to the defective car or other vehicles.
If you're flying and have a catastrophic failure, you may simply fall out of the sky. Good luck surviving that. But given how flying is regulated, at least your odds of killing other people aren't as high.
Unless you have full-scale structural disintegration----possible, but highly unlikely unless the pilot has made some serious errors in judgment----you will not simply "fall out the sky". You will glide the plane towards an open area if possible. It's even possible to "settle" a plane (relatively) safely onto a forest canopy if necessary. In-flight fires are another rare hazard which could hinder the pilot's ability to land safely.
Your point about regulation is sort of right and sort of wrong. On the one hand, the regulations requiring pilots to be familiar with and practice emergency operations means that the chances of them accidentally killing people on the ground are low. Air Traffic Control will not necessarily be a factor in that, however, which is what I think you were implying. Many planes fly under visual flight rules without ever talking to ATC. Some don't even have radios. In fact, Light Sport pilots----who may operate the Terrafugia Transition, it is classified as an LSA----are forbidden from operating within controlled airspace (except class E).
The technology might be there but it is meaningless and absolutely impractical. There are so many other problems that we aren't yet mature enough to handle. Think of all the people who are speeding, driving drunk, failing to obey traffic signals, and illegally tuning their cars. Think how much worse flying cars would make those problems.
Speeding: Rarely a problem. Only a few bits of airspace have speed limits, and most piston planes can't even achieve those speeds.
Driving drunk, failing to obey instructions or airspace restrictions: One has to rely on pilot discipline and common sense here, same as for driving. The penalties for violations would be severe, of course.
Illegal tuning: Slap an "Experimental" registration on the plane and you're good to go, pretty much. (Regulations do require that all major modification work be done by a license Airframe & Powerplant mechanic. Pilots are only allowed to do basic preventative maintenance such as oil changes. But if you happen to be both, cool!)
Also, there is a serious perception problem with safety regarding the flying car technology. What a regular car breaks down or stalls, you pull over or simply sit there. What happens when a flying car breaks down or stalls?
Stalls, in the aerodynamic sense, are no big deal for most designs of plane. Spins are more dangerous, but stall/spin awareness is part of basic training.
As far as engine failures go, as I said the vehicle will glide. It's up to the pilot to get it safely onto the ground at that point, but it's not an insurmountable task. In the worst case, some small planes are starting to be equipped with airframe parachutes these days. If all else fails, pull it.
