To be fair, as best I understand it an airplane cruising at altitude is not very hard to pilot. Nothing to run into, nobody merging into your airstream- nothing much more complicated than "steady as she goes"

I believe takeoff, ascent, landing and descent is still done by pilots.

Additionally, trouble with cars is, they have evolved for 100 years around sight as the primary navigation function. Planes almost never had that luxury, so they have relied on instruments for a long time. Computers are good at instruments, not so good at sight.