Behave yourself or risk losing that seat on the plane

Southwest Airlines welcomes checked luggage -- as their entertaining TV ads remind us -- but not always their passengers.

Just last month, the airline booted Green Day frontman Billie Joe Armstrong off a flight because his pants sagged so low his boxers showed. A few weeks later, actress Leisha Hailey and her girlfriend faced the same fate after kissing (excessively, according to the airline).

Southwest is not alone. Delta removed a woman after she questioned the pilot's sobriety. Canada Air Jazz did the same to a man with a strong, unpleasant odor.

Circumstances that can get you a one-way ticket back to the terminal (at least temporarily) are similar from airline to airline and include appearing intoxicated, going barefoot and having, in the words of Delta's Contract of Carriage, a "malodorous condition." And then there are the subjective, vaguely worded rules: when "conduct creates an unreasonable risk of offense or annoyance" (Delta), or wearing clothing that is "lewd, obscene, or patently offensive" (Southwest).

Just to be safe, I suggest fliers cover up undergarments, don't sweat as they run to the gate and be Minnesota nice -- to everyone.

Certainly, anyone whose behavior threatens safety does not belong on a plane, and no one wants to sit mere inches from a smooching couple or someone doused in perfume.

But on sartorial matters, I hope the airlines get more specific in their guidelines or at least err on the side of tolerance. I also wish people would polish their appearance when they fly. I've seen sweat suits in the air that are worse eyesores than a little show of boxers, especially if the undies are in a pleasing plaid.