When traveling for football during college, we had the following celebrity encounters:

October 1996 - DFW American Airlines Terminal
Sandra Bullock and Matthew McConahagh (sp) browsing the gift shop

September 1997 - DEN->LAX
Huey Lewis and the News
Huey signed my game plan and sat in First Class while the News sat in coach.

Also ate next to Ice Cube in Vegas, and flew to Omaha from Denver with Hulk Hogan.