(re: PQ2 Terrorist help needed!)
Did you drink alcohol on the plane? If yes, that keeps you from being able to shoot straight.
If that’s not it, all I can think of is if something happened between arriving at the airport and getting on the plane – like, did the security guard grab your gun when you went thru the metal detector? (He does this if you don’t show your badge soon enough.) Anything else that could have knocked out the sights, that you could have avoided at the airport?
I have this strong feeling that I had this very problem, I just can’t remember the answer. It’s been 13 years since I played the game! (And alas, my hint book is long gone…)