[lmm]

It's a lot easier to avoid hitting anything in the air, because there's a lot more space up there, and a lot more directions in which to dodge. During the war we sent teenagers with <20 hours of training to fly in combat (and while many of them died it wasn't because they were crashing into each other or the ground).

[nknighthb]

It's not so simple. A worst-case scenario for a flying car might be nose-down terminal velocity into a crowded building. Or even faster, if the driver were deliberately accelerating into the building, trying to use the car as a kinetic weapon.

Scheduled commercial airline flights are quite safe, which makes people think "flying is safe", but general aviation, which lacks many of the strong controls that scheduled airlines have, is much worse[1]. I would expect flying cars under manual control of typical drivers over a crowded city to be much, much worse still.

[1] http://www.ntsb.gov/news/2012/120427.html

[pavel_lishin]

While that's true, there weren't a lot of cars on the road to hit during that time, either.

Imagine the commuting public of the New York City region, all in the air above Manhattan.