Continuity mistake: When the "ghost" is first seen, it is mostly obscured by a curtain; only its right shoulder is visible. In the next shot, however, it is right in the middle of the window, and nearly the entire cutout is exposed.
Continuity mistake: When Peter comes home, he goes to his mailbox and pulls out a note, then has a newspaper clipping. When he goes upstairs and comes walking in, he's got sunglasses on. I'm sure he would put on sunglasses in the building just to walk upstairs.
Answer: Yes. Before 9-11-2001, non-passengers were allowed to go into airports and go to any of the gates. A lot of times, people would accompany friends or family members to their gate or be there for their arrival. And you wouldn't need a passport just to go to a gate with an international flight. In fact, one time I went to pick up a friend (pre cell phone days) and didn't see her come out and was afraid I missed her or didn't see her. So I asked one of the airline employees if she could check the manifest list to see if my friend was even on the flight, which she did to help me out. Things were much "simpler" back then.
Bishop73