@ Liudvikas:
First of all making a flying car is now impossible, for example A Rocket Which is size of a building currently cost 10 million gas money,40 million materials. Now saying that to an ordanary car would cost a few 700,00. Im sure not everyone in the world is willing to spend 0.7 million just to fly when they can do $1000 instead. Second its impossible to lift a car, make it go ‘hummmmmmmm’ and just make all 16+ teens in the worlds be smart enough to get a good enough job to get 700,000 and a pilot licences. The materials to make a “flying car” would have no profit. for example a small jet currently cost 1 million to build for 1 person. 5 peoples wieght would cost atleast $40 on fuel each 10 miles not very cheap… Also imanage flying things in the air, a drunk person can crash down and not just hit him self but someone on the side walk/street.Oh look how would we make streets in the air?? how many people would hit buildings, Look at some countrys they dont even have Normal wheel cars yet. Lets wait a few more years or decades or centruys.

@ Liudvikas:
I think the main difficulty of making an automated ground car network is the transition period. Having ad-hoc human drivers coexist with auto-pilot cars seems like trouble to me. Doing a hard shift without a transition period might be possible, but it would depend heavily on economics.

As to the implementation, the logistics required to handle it shouldn’t be that difficult: knowing where everyone within a certain radius is, where everyone is going to and what routes everyone is taking to get there, it shouldn’t require too much effort to get a reasonably efficient heuristic approach working. Getting the cars to communicate with each other and the control systems is easy. We already have a similar system in place: the cell phone network. Unless we want to have these cars travel super-fast, any kind of communication latency (including computation time) should not cause trouble. Of course there would be built-in failsafes (say, if communication with Traffic Control is lost, the car gently stops and broadcasts a warning to everyone nearby).

The same algorithms can be used for the sky version, adapted for the possibility of having more routes available. We can model the sky as a graph, just like we do with the roads. It’s a heavier graph, but the same algorithms would work as well. Even though the sky has no obstacles, isn’t it easier (and not that much worse, I guess) to work as if it did, i.e., to have aerial traffic lanes?

@ Martinho Fernandes:
That is true, but currently you seriously need to want to get around faster to spend a lot of money. And flying cars aren’t accessible to everyone, like regular are.

Global auto-pilot for ground-based cars would be way harder to implement. Sky is mostly free of any obstacles after all.

I totally agree with IceBrain. Cars suck. We mostly use five-seat vehicles to transport one or two people, when we can use hundreds-seat vehicles to transport hundreds of people. The best part is, if transportation worked as IceBrain put it, we would reduce GHG emissions as well.

@ Liudvikas:
I don’t see how we could devise ways to make flying cars cheaper or more effective engines such that flying cars become better option without also allowing us to make regular ground cars an even better options. It might be doable, I just don’t see how.

Also, a global auto-pilot system like you suggest would be great for our current ground-based cars. Unfortunately, it would be a nightmare to implement with the current state of affairs.

@ Zel:
Wouldn’t the magnetic fields required to bring a car and its cargo aloof be too powerful to allow vertical stacking of car lanes? Sure we could make cars out of plastic, but there will always be some electronics in there. And the other cars own magnetic fields. Seems a little too complex to get working. And without stacked lanes, what you get is just a normal car, but it doesn’t touch the ground. Cool, but not much of an improvement over what we have now.

@ IceBrain:
Yes, but there are way less airplanes. We would need a new system if suddenly there were as much flying cars as there are humans.

As IceBrain said, airplane cars probably wouldn’t solve much. Where do traffic jams mostly occur ? Every day in major arteries linking suburbs to the nearest city, or at the beginning/end of holiday seasons. Having such flying cars could help with the latter, but the former would see no improvement at all. You would get closer to the city faster, but would have to wait forever circling a crowded sky for an available lane on which to land.

Anti-Gravity cars on the other hand would solve both. There are ways to defy gravity without wings or air movement, electromagnetism and supraconductors for instance. Point is, it’s certainly possible to have what those crazy futurists dreamed of : small, silent personal vehicles capable of stationary flight. I don’t know of any flying car attempt that didn’t end up turning the car into an airplane or a helicopter at some point. Maybe it’s time to look for another solution ?

@Liudvikas: there’s already ADS-B, a system where airplanes continuously broadcast their current location to nearby airplanes. It could very well be adapted to flying cars.

But I disagree that “cars work well enough”. We spend years of our lives stuck in traffic (well, plenty of people do, I don’t). The problem is that these personal ‘copters don’t solve that problem.

Personally, I think cars are ill-suited for most transportation problems.
For 3-10 mile trips, mass transportation systems like subways are the most effective solution, and for larger trips, trains or even airplanes are cheaper and faster.
For trips up to 3 miles, people should walk or cycle.

Well technology still needs to advance a little for flying cars to be a viable transportation option. The technology needs to get cheaper, before it can be marketed to the masses. Sure I would like to travel faster, but I definitely don’t want to spend shitload of money on the car and have it eat gas several times faster. Not to mention I’d need to get a pilots license which is harder and more expensive to get.
These things need to be done before flying cars can be an option:
1. Cheaper flying cars.
2. More effective engines.
3. A global autopilot which could see every single car on the sky and communicate with them in order to make travel safe.