What is Nasa/US funding coming too, an embarrassment. They cancel their measly inadequate funding for investigating the feasibility of alternative space propulsion technology, cancel their measly funded research into a system for flying car. If any of these things came through they would greatly change the world, while producing great wealth for "US of A" manufacturers. A few people accuse the government over there of being un-patriotic. It is well worth the measly amounts they put in, in case they actually work.
There are an awful lot of problems to overcome flying, it is not as simple as driving a car. Handling is dangerous, not like a car that relies on gravity and friction to hold to a road. Fuel economy is also an issue (remembering that Flying cars are to use skylanes apparently, not quiet as the crow flies).
In my own designs ideas I have a number of potential solutions to over come many issues (I am an innovator) but don't aim for economy (or cost) of more than a V8 car. But if they claim 25mpg, I might get 50mpg, but using similar technology you could drive a car at equivalent to 100-200Mpg.
You really need something that generally floats with low wind resistance, that can divert all it's power to propulsion. The link on airships. Been thinking of this, but you again are subject to wind forces. I have an proposal to cheaply get around this and stabilise in high wind, but the wind is as controllable as waves when you are dealing with huge surface areas. On a car I might be able to make it nearly as safe as a normal car and stable (but again, it would make a car even better) but an air ship is a big sail full of gas and not as safe. Also, landing airships for a neighborhood might also prove "undesirable". So you get to alternative (Startrek) technologies, with only one example claiming possible fruition that I can remember in my lifetime, and Nasa canceling funding on research that could go towards conserving energy in terrestrial transport and manufacture for competitive advantage through the propulsion research (ohh, yes boys, that does seem to better fit your governments economic agenda).
One of the proposals Nasa was investigating (and I do hope this one is still going somewhere) was for a propulsion from a new form of reactor that generated a magnetic field to propel off the outflow from the sun. Could greatly save on the costs of future missions compared to current ongoing rocket and ion propulsions strategies.
With China investing so heavily in research (even the government) the US better get off their collective backsides. The west lacks the guts to get off it's backsides and do something, we have become whiners on what we can't do rather than what we can do, and progressively when it is something we can do, it is about doing something to enforce what we cant do (environmental technologies in particular). Might as well go to China, except for the way people get treated (but that is changing too).
But if flying cars do go ahead, it might be possible to make a road last for a thousand years if it is not used much (by the few remaining drivers, walkers, and horse riders, and transport).