There's been discussions for years on whether or not the level of automation in modern aircraft causes pilot training to lapse due to misuse. Self-driving planes are much easier than self-driving cars because there is empty space on all sides of the plane pretty much at all times. Autopilot is already generally speaking "a thing", with the exception of takeoff and landing.

Bear in mind even in takeoff and landing scenarios, unlike a public roadway, the airplane has pretty exclusive use of the runway as well.

Pilots are very unlikely the primary cost of aircraft trips. Things like jet fuel are probably much more of the cost driver.