In Planes, where there are 3 or more levels of redundant power and hydraulic systems with an ability to fail down to a limited mechanical operation mode if all the other backup systems fail. It's proven because they designed it with a stupid level of failsafes.
There's no redundant power in the Tesla Drive By Wire system, if the power is cut, you lose the ability to steer. You've got brakes, but you're without any of the assistance that the car normally provides. It's so fucking stupid I can't believe it's allowed on the road. If anything goes wrong that cuts power while you're in motion, you're suddenly captive in 3.3 tons of stainless steel without crumple zones, without the ability to steer, with naught but your unaided foot on the brake peddle to determine your outcome. It's nothing like the multiple layers of failures you'd have to endure to find yourself in trouble in a plane both for the power and the hydraulics.