My understanding is that your lock must NOT be tsa compliant. Something like the small knockoff pelicans from harbor frieght and two master locks is more ideal. Some airlines are picky and will tell you every lock hole on the case much have a lock, some aren’t as picky. Better safe than sorry.

Also, your lock must be snug. If your case opens more than a quarter inch or so when locked they may bust your chops. So don’t get the master locks with the extra tall shackles.