I'm currently on a bit of a "world tour" (Amsterdam, Cyprus, London and New York City) and have a suggestion or 2.
1. Water. Plenty of clean water. I carry a liter in my carry-on.
2. Purel or similar hand sanitizer. Wash your hands constantly.
3. A small towel for your lap so the coffee lands on the towel, not your last pair of clean trousers. It makes a fine littl epillow for your head on the plane and at the airport. Douglas Adams had it right - always bring a towel.
4. Tiny "bud" style headphones. Two jobs - ear plugs to keep the noise down and you can listen to the movie if you want.
5. Food - some snacks other than the wet, too-hot or too-cold crap. I carry beef jerkey, granola and dried fruit leather.
6. Anti-Diarreah medicine. You can safely DOUBLE the dose of Immodium-AD products when you really need it. Trust me on that.
What you're putting together is an ASK (Airport Survival KIt). A plane has all the tools and equipment you'll ever need in the air. It's the darn aorports that are horrid.
see also
http://www.focazio.com/equipped/air/air.html