P travels about 125,000 miles a year on airlines. And over the years he's fine-tuned his luggage based on ultra-light backpacking philosophy. It's a system that has served him very well for many years now.
Here are his rules for lightweight airline travel.
1. Never check luggage--always carry on. Admittedly, P gets priority boarding, so there is always space for his bag. But even when he is flying on smaller planes with no overhead storage, it still works out better than checking your bags.
2. Now that we know the bag is going to be smaller, he packs with an eye to lightweight and reusable items. He onlys take a few shirts---all of them wrinkle free so that he can wash and wear them on the road. He uses his backpacking undies as well, and socks that will dry quickly. Those get washed in the evening and are dry the next morning. Pjs are the same ones he uses on the trail.
3. One nice sportscoat and a couple of pairs of slacks for meetings. And he'll take a sweater, scart, and umbrella in the winter. When it is really cold, he puts it all one, including the Pj shirt underneath. Just like backpacking.
4. Slip on shoes and no belt, so that security checkpoints go quickly
5. A small toiletries bag, charger for the Blackberry, and that's about it.
6. P wears a very comfortable cotton dress shirt and indestructible slacks, with the sportscoat on the plane. That's saves weight in the bag and keeps the coat from getting wrinkles.
If he needs a laptop it goes on top of everything.
That outfit will get him through a week of travel to Europe, and weighs about 22 pounds--including the suitcase and all its contents.
Then again, he always says that if he has his passport and credit card, that's about all he needs to get by!