Keeping in mind that other Users can still play the game....
This only takes a few moments, once the save file has been located. It also assumes that even if all players are on the same save,
that your stats are the only ones that have somehow been corrupted.
- Even games that have only one save have a save file in one of your Username folders, and you can rename the save file,
or move it to another location temporarily.
The exact location for your 'Airport City' game save file can be found ....
https://www.airportcitygame.com/threads/backup-and-save.10605/
Once the save file is renamed or moved, start a new game and new files will be created. If the game does not lock-up again,
the original save is suspect.
If the game still locks up, you can delete the new save file and change the original save files name back to what it was.
(or move the old one back again) and you won't loose your progress.
If the game still locks up, going back to doing more arcane stuff that is seemingly not directly related to only one of the games players
may somehow fix the issue.
[EDIT: I just realised that your original saves may not be there anyway if you have reinstalled the game.
What else then might you be doing the other player are not, which may lead to locking-up\crashing ? ]
.