Forgetting, and not really caring, that I was in flight, I quit the game, then left it for about an hour and a half. I get back on, try to leave, it says I'm in flight, so I press the handbrake, or whatever,  and nothing happens. I suppose that the sound didn't play, and try to leave again, says I'm in flight. I replace the lever, nothing. Now I'm stuck. Help?

I dont think there is much to do in this situation. Personally, I would just /suicide when a staff member is on ask for my tardis to be summoned.

Singleplayer? Multiplayer (If so, which server?)?

This may be Singleplayer. This glitch has happened to me a lot in singleplayer causing me to have to rebuild another TARDIS.

This is in singleplayer

Are you in survival or creative? Also, is keepitems turned on?