Modern aviation includes fully autonomous modes though. An airplanes autopilot is simpler than a car's autonomy, but they accomplish essentially the same goal: get you from point A to point B with no human interaction. AFAIK, even takeoff and landing can be done mostly autonomously on modern aircraft.
If anything, airplanes prove that machines doing most of the work and humans stepping in only when necessary is a proven model.
That's not at all the same thing. When commercial pilots engage the autopilot (or autoland) they're still actively flying the airplane, just operating at a higher level of abstraction to decrease the workload and fatigue. They're not sitting back and playing Candy Crush on their smartphones.
> If anything, airplanes prove that machines doing most of the work and humans stepping in only when necessary is a proven model.
Airplanes have far less traffic to deal with. And the points at which they deal with traffic (e.g. takeoff and landings) is completely controlled by humans, including many humans outside of the plane.
Apparently pilots generally prefer to not use them. Not because they don't work but because pilots still need to be on alert and so its easier to just land manually.
They're used in low visibility conditions with relatively calm weather, but don't work well in bad weather.
A significant number of air accidents have resulted from unintended interaction of the autopilot and the pilot. Usually through some level of confusion about whether the autopilot is engaged or not (and 'how engaged', aircraft autopilots can have a complicated array of modes). There's a lot of learning in autonomous system to human interface design embodied in modern aircraft autopilots.
When an unusual situation causing the autopilot to disengage happens in the air, you often have minutes of time to deal with and correct the issue, almost never less than 5-10 seconds. In a car, you're lucky if you have even a single second, and that's just not enough time to take over.
Automation for airplanes is really so much simpler, a lot of that thanks to a lot of hidden human effort in keeping planes well separated so pretty much all it has to do to fly is keep course and control. If that was all we had to do for cars it'd be pretty simple.
If anything, airplanes prove that machines doing most of the work and humans stepping in only when necessary is a proven model.