Ah, but the earth is flat. Gravity simply warps space around the center of the earth's mass until the flat plane touches on the other side.

That'd be a hell of a kaboom considering the Earth is quite a ways away.

Liability isn't too much of a problem in my opinion. Insurance will cover any issues, and rates will change based on the performance of the autopilot. As long as the autopilot performs equally as well as drivers across the entire set of cars insured, then the insurance rates will be the same, people will pay the same rates, and insurance companies will shell out the same payments. An accident wouldn't cause rates to go up, but good driving records wouldn't bring the rates down, and everyone would pay rates based on the area they live and drive in. A horrible autopilot would be detected quickly by insurance companies, and that would be the fault of the manufacturer, a poorly modded autopilot or poorly maintained vehicle would also show up as an anomaly and would be the fault of the owner. Uninsured drivers would be responsible for themselves.

"No reason to do this. As a fucking human being this is totally unwarranted."

FIFY.

Bogota hired a few hundred mimes about 6 years ago to make fun of people breaking traffic laws. It was reported to be quite effective actually as the people were more apt to change their behavior because of shame then because of fines. Probably much cheaper than radar as well.

I can see where they could use stored electricity to shut engines off when landing to reduce noise, charge at the gate, and take off without engines as well.

That alone wouldn't affect efficiency necessarily, but would probably allow the use of louder engine types that might be able to reduce efficiency, and it would reduce the opposition to airports allowing them to be placed in better locations.