Some variation of what's already been listed, but for international flights I add a travel toothbrush/toothpaste set from WalMart (about a dollar) and deodorant so I can freshen up before we land. Wet wipes are helpful in that regard too.
Not quite air travel gear per se, but related to longer business trips...
How many pairs of pants do you guys fly with? When I travel, I'm gone for a week or more and trying to pack a separate "outfit" per day is bulky. I'd like to get a week's trip into a carry-on so I can avoid dealing with baggage check. I'm not wearing suits, mainly slacks/khakis and button-down shirts.
Chris