Putting your Buick-sized suitcase on a rolling cart does not make it carry-on luggage. Though you might be able to physically carry the item, and maybe even shoehorn it into an overheard bin, anything bigger than a backpack should be checked.

Nonetheless, nearly every person on my recent flight to San Francisco boarded the plane carrying a steamer trunk on wheels. Instead of the magazines, snacks and perhaps change of underwear people traditionally bring with them, passengers now lug all of their bags onto the flight.

This saves you the trouble of waiting in baggage claim when you land and removes any chance of your luggage reaching a destination other than its intended one. Unfortunately, to achieve these desirable benefits you must inconvenience every other passenger on the plane, which gives them the right to do the same to you.

As soon as one person violates the rules, the entire extremely fragile air travel society breaks down. Normal people quickly become an uncontrolled mob of inconsiderate, cart-wielding maniacs, and the entire process of boarding moves slower than a Seniors golf tournament.

This changes the relatively easy process of getting to your seat into a contest somewhere between Roller Derby and American Gladiators. Push ahead of as many people as you can and bash everyone else in the head in order to stake out prime space for your oversized luggage. Of course, the time you save on the ground is more than made up for by the added hours spent crammed into a crowded plane, but people never give that part of the equation much consideration.

Airlines do very little to solve this problem, making only a token effort to stop people from putting wheels on their furniture and dragging it on board. They do place those metal "if it doesn't fit here" things around the airport, but the real limit seems to be whether a given piece of luggage can squeak through doorways.

If it's smaller than a grand piano, but still big enough to slow down the process of getting on or off a plane, at least 50% of the people on any given flight will try to bring it on board. Airlines pretend they dislike it when you do this, but I'm guessing they actually look aside because it gives them justification for delaying your flight.

I've had takeoffs delayed for missing engine parts, crew members oversleeping, and everything short of the in-flight movie not being rewound. Because of that, I'm against anything that shifts the blame from airline to passenger.

It's difficult to complain about over-booking, phantom weather problems and the other nonsense air carriers use to justify late flights when you've made everyone wait so you can get your Volkswagen stowed away. Carry-on items are those that directly impact your enjoyment of the flight - I'd suggest a pack of gum and a paperback. That doesn't mean a jukebox or a treadmill.