Elon has talked about building planes. he says what he has learned from building cars spaceships and starlink would make his planes world-beaters.
However, he doesn’t have the time. He just has too much on his plate.
Its a deep question as to whether he can hire the staff to run his companies without his direct supervision. It didn’t appear to be the case 4-6 years ago when he made the comment
Elon needs a #2. Bill Gates had that in Steve Ballmer. But Ballmer wasn't quite the visionary Gates was. But he kept things running.