We haven't solved this on the ground. We just accept that 1 million people die in car crashes each year and something like 10 million sustain serious injuries that leave them scarred for life. Also many that die and are injured are NOT the culprits, they're just innocent bystanders. We also destroy property constantly with cars and suffer from horrible congestion everywhere.

There's a lot less space when you consider how many airstrips there are in the world. Imagine if everyone on the highway in a city had to get on and off on the same exit ramp.