[FabHK]

There are far fewer obstacles in the air than on the ground.

If you put a plane on autopilot and then go read a book for some hours, most likely nothing bad is going to happen (particularly on IFR, but even on VFR, realistically).

Tesla's autopilot is more advanced than aircraft autopilots, I'd say, yet more dangerous (for now) because of all these darned cars and trucks and pedestrians.

In that sense, "Autopilot" was an unfortunate and overly ambitious name.