Apart from the training and the fact that pilots work in pairs, there’s a host of differences that make a planes autopilot task and behavior fundamentally different from what Tesla misleadingly labels autopilot:
Planes operate in a space with good visibility, any obstacle will be visible with ample lead time.
Planes operate in controlled space, with dedicated and verified spacing between traffic participants, allocated by an external traffic control. Collisions are not rare because pilots jump in within split seconds to avoid them, but because traffic control routes planes away from each other if they converge.
The planes autopilot is in fact less capable than what the teslas autopilot pretends to be. Its limitations are fairly well understood by pilots.
A planes autopilot doesn’t dump the pilot into a “you’ll crash in a second” situation. Handover from autopilot is a different process than what Tesla expects. The planes systems are designed with human psychology and limitations in mind, because of the comparatively high regulatory bar.