[alberich]

>> Not to mention that it's impossible to simply stop in the air.

What if they invent one that flies like helicopters? Who knows what will come in the future...

[sp332]

If you cut the power in a car suddenly, you can probably avoid serious damage or killing anyone on your way to a stop. Not so much in a helicopter.

[alberich]

Hm. I thought the post was referring the troubles of maneauviring during a slowdown, as airplanes can only go forward.

If falling of the sky is the trouble, you can still use parachutes as a safety measure. Like this one (http://en.wikipedia.org/wiki/Ballistic_Recovery_Systems).

Anyways, I don't think flying cars are impossible. We just don't have enough technology yet to make it viable.

[ajuc]

Most helicopters can autogyro - that means they can land without working engine, using air flow to speed up the rotor, and then using the rotor to slow down the fall to relatively gentle landing. More or less like the seeds of some trees fly.

Same goes for gyrocopters, which are sth in between regular plane and helicopter (they have powered propeler to gain horizontal speed, and unpowered rotor that is speed up by autogyro effect that replaces the need for wings).

Of course in dense 3d traffic you may collide with sth before you can slow down the fall, so there will be a need for some system that sygnalizes everybody below you to quickly get out of way.

[gduffy]

Helicopters can be landed softly without power, via autorotation.

It's not hard to imagine an autonomous helicopter that can manage autorotations. Some drones already do. But for people-carrying operations, it would need to have an extremely fine-grained terrain database (better than we probably have today) to pick suitable landing spots and avoid low-level obstacles.