How was John able to bring his handgun on a commercial flight to Los Angeles?
I know that this was made long before 9/11 and the filmmakers tried to "hand-wave it" by saying that John could get away with it since he's a police officer, but still...
https://www.quora.com/Was-John-McClane-allowed-to-carry-a-firearm-on-a-commercial-flight-in-the-movie-Die-Hard
https://www.reddit.com/r/explainlikeimfive/comments/1syf4z/at_the_beginning_of_die_hard_john_mcclane_carries/
https://www.defensivecarry.com/forum/concealed-carry-issues-discussions/60527-carry-airplane.html
http://www.imfdb.org/wiki/Die_Hard