I find it interesting to watch family reunions at the airport and try to figure out who's who in the family, e.g., kid back from college for the summer, grandparents coming for a visit, spouse back from business trip, etc.
Be sure to catch the action at the baggage claim too, itsbetteronamac. You might consider doing a fast-motion scene there, as the baggage areas fill up, empty, fill up, empty and the luggage appears, disappears, appears, disappears.
Perhaps you'll catch a sports team getting on/off a plane. They are usually lively bunches of travelers. It's sometimes fun to ride on a plane with a team too, unless you plan to sleep on the flight. And I'm always glad when they aren't staying on the same floor of the same hotel as I am!