“Autopilot” in a plane keeps the wings level at a set heading, altitude, and speed. It’s literally the same as cruise control with lane-centering, since there’s an altitude issue on a road.
Factually incorrect. There are autopilot systems on planes now that can takeoff, fly, and land the flight on their own. So yes, "autopilot" is EXACTLY what people are assuming it to mean in many cases. Especially on planes that they would typically be accustom to... which is the big airliners.
Now where you're missing the point... There are varying degrees of autopilot. And that would be fine and dandy for Tesla's case if you wish to invoke it. But considering the company has touted it to be the "most advanced" and "Full self driving" and "will be able to drive you from california to new york on it's own". They've set the expectation in that it is the most advanced autopilot. Akin to the plane that doesn't actually need a pilot (although one is always present) for all three major parts of the flight. No tesla product comes even close to that claim, and I'm willing to bet they never do in their lifetime.