I haven't checked a piece of luggage since I climbed Mount Kilimanjaro five years ago--and believe me, I wore every item of clothing I brought with me, sometimes all at once. (Okay, I had to check a bag that time I brought five bottles of wine home from Argentina. But they all fit in my carry-on; I just couldn't bring them into the cabin because of the TSA's no-liquid rules.) I also traveled for six months with a single backpack that weighed about 30 pounds and never had to pay a single excess-baggage fee. Yes, dear reader, it is possible to wear the same thing more than once and to wash your underwear in the sink. I even did it in Cannes, France, and the fashion police didn't arrest me.

Every pound of luggage that we carry with us onto the plane means that more fuel is required to make the same trip. If we all pack a little lighter, we can reduce the amount of fossil fuels burned per flight. It's certainly not a solution to our energy problems, but every bit helps. For some of us, it's going to take the threat of an airline fee to rethink our vacation wardrobe, just like it's taken the threat of seven-dollars-a-gallon gas to slash the market for SUVs.

There are problems, no doubt, with American's proposal: Is there enough overhead space on planes to fit every passenger's carry-on? If not, are those who end up in a late boarding group--through no fault of their own--going to be penalized for having to gate-check their suitcases? I suspect that the fee won't stick, since no other airline has yet followed suit. Still, it should be a lesson to us all: Packing light is the green way to go.