New this monthFactual error: The exchanges between the bad guy pretending to be an air traffic controller and the pilot of the doomed aircraft are not even close to realistic. Air traffic control communication is almost its own language. The FAA handbook says, in part: "Brevity is important, and contacts should be kept as brief as possible. Jargon, chatter, and 'CB' slang have no place in ATC communications."
New this monthFactual error: Transport aircraft do not have ejection seats; only fighters, bombers, and attack aircraft have them.
Answer: In the first movie he's a New York cop visiting his wife. In the second Die Hard, he tells the airport officer that he's LAPD and moved there because of his wife's job. In the third Die Hard film, he most likely went back to New York because of marital problems and became a New York cop again.