TSA authorities can fine you $10,000 for leaving the airport

[Happy Monkey]

Originally Posted by Lamplighter

1) Some may think it is to keep planes from flying into buildings.
But that can be prevented by a secure door into the pilots cabin.

You don't even need that. You just need the passengers to remember 9-11, and you won't get any more hijackings. 9-11 worked because the passengers expected the planes to land somewhere, followed by some sort of hostage negotiation. That is no longer the case.

(bombs are a different issue)