We manage to keep some rather smart people in jail long term, even though the jailers are not as smart as some of their prisoners.

AIs can attempt to cross air gaps, but air gaps vary in terms of their effectiveness. I.e. if "air gap" is just some air between two machines that both have wifi chips, then yes the AI may be able to cross that by hacking the wifi system.

If "air gap" is AI running on a server with no wifi chip inside a faraday cage under a mountain powered by a generator then I'm not sure how the AI would escape on its own. Seems like the physics would contain it.