Walking through the airport the other day, I noticed a sign by one of the boarding gates: “Don’t be a bin hog,” it declared, suggesting that prospective passengers use the available template to measure and be certain that their carry-on bags would fit the approved dimensions.

Now, without a doubt, there are passengers who carry luggage onto their planes that is really too large to be reasonably accommodated in the cabin. But, for the most part, the problem of increasing cabin clutter is that passengers, lacking confidence in the airlines to quickly and efficiently return their checked luggage, are carrying on more baggage.

Airlines can respond to this kind of challenge in two ways. They can do as this particular airline, Southwest, has done and seek to bend passengers to company convenience by the strategy of calling customers nasty names. This is, in fact, the preferred strategy of most airlines.

The alternative would be to do what most other kinds of businesses are taught to do: Address the problem that’s causing customers to carry on more luggage.

Notably, one airline, Continental, has responded to the problem by ordering planes with larger overhead storage bins. In one celebrated instance, it sued Delta (with which it shared a concourse in one airport), demanding the removal of templates designed to prevent customers with oversized bags from ever getting past the security checkpoint.

Now, it is not the purpose here to extol the greatness of Continental Airlines, which has its own problems, but rather to point out the aberrant concern for the customer in a business where customer abuse is the key to success.

After all, this is the industry in which one airline could proudly boast that it didn’t serve meals in flight and expect to improve its image.

The basic reason airline travel has become the way it is these days lies in the airlines’ mastery of the economics of their business. Quite simply, they have figured out exactly how to price their product in order to shoe-horn the largest possible number of people into their aircraft.

Unlike most consumer transactions where pricing is a fairly crude approximation, it is high art in the airlines. A customer shopping at the grocery store faces the same price for a can of beans regardless of how much the customer wants the can of beans, how much the customer can afford to pay for the can of beans, or whether the customer is willing to conform to the convenience of the store in order to get the beans for less.

A customer can achieve some savings by buying in bigger quantities or by clipping a coupon out of the newspaper, but basically the beans are priced to reflect what the typical customer will pay.

Such a scheme means that some customers pay much less than they would be willing to pay, while other customers pass on beans as too pricey even though the store might be able to make money at the price they would be willing to pay.

With the airlines, it is different. Tickets are artfully priced to reflect just how badly a person wants to travel on a certain day and time.

Nothing gets left on the table. The overall supply-and-demand structure is diced into an array of substructures so that no class of customer pays less than he is willing if the airlines can help it, and no profitable customer is priced out of his seat.

The airlines even operate a kickback program (frequent flier miles) designed to sever the personal interest of the business traveler from the interests of his company. Indeed, airlines have gotten so efficient at their business that they are now even sending out last-minute e-mail notices with bargain basement fares trying to drum up interest if they discover that by some mischance they have some excess capacity left on some route.

In such a pure economic bazaar, the notion of competing with each other by offering better service is a quaint, atavistic notion. The invitation to fly the friendly skies may be the slogan of United Air Lines, but at this point, it is a purely vestigial remnant of the company’s corporate history rather than an active approach to selling its services.

In the drive to push prices ever downward, or perhaps out of the sheer perverse pleasure in displaying what level of mistreatment they can get away with, airlines have stripped out as many elements of customer service as they can.

If passengers on American Airlines are fed at all, it is likely to be from a plastic bag-o’-grub they are invited to grab before they board their planes. Southwest does not even offer a reserved seat, preferring instead a system of cattle-stampede seating that helps allow the airline to maintain the shortest on-ground turnaround between flights in the industry.

Meanwhile, to maximize the carrying capacity of the airplane, the seats are getting smaller and closer together. When Boeing first started building jetliners in the 1950s, it relied on a railway industry study that determined the minimal acceptable seat size for railway travel was 18 inches in width. Current configurations on 737s call for seats less than 17 inches wide.

Anyone who has been to his local Shoney’s is aware that this seat shrinkage on the airlines is running counter to the trend in the size of the median American buttocks over the last 40 years. (For comparison, the club seats at the new stadium are 21 inches wide, while even seats in the peasant sections are 19 inches wide.)

At the same time, the distance between seats has shrunk from a normal seatback-to-seatback interval of 35 inches to 32 inches, with 31 inches climbing up over the horizon.

Asked about the shrinkage in personal space, airlines tend to shrug the matter off, noting that surveys indicate that the biggest single factor in determining whether passengers are comfortable and happy with available space is whether the center seat on their row is occupied or vacant.

While this may be true, it is also true that the airlines are working more diligently than ever and with greater success to fill up those center seats, as increasingly sophisticated yield management is producing ever-higher load factors for the airlines.

The airlines are even pondering charging passengers to give back what they have taken away. United is considering a new travel class called Economy Plus, the Wall Street Journal reported recently. The only amenity in the new class service would be seats spaced at the 35-inch interval. They would be available only for high-usage frequent fliers and passengers paying full fare.

One of the reasons that the quality of airline life seems to have declined so sharply is the lack of competition. While it is true that the United States has many vigorously competing airlines on the national scene (and on international routes), outside of major markets, most travelers face near monopolies with a single dominant carrier operating a fortress hub with a minimal presence from a smattering of other airlines.

The other major airlines (and no-frills discount carriers) keep the dominant player honest, but not to the point of improving the cuisine. (Nashville is in the bizarre situation after American’s cutbacks and Southwest’s growth of having the discount carrier also be the dominant carrier, putting pressure on the smaller players to keep prices down.)

But if airline travel is uncomfortable these days, the main reason is that passengers have made their own tacit statement to the airlines that the most important factor in their calculus is price. More people are traveling by air now than ever before, and they do so because the airlines have found ways to capture every dollar of the consumer’s willingness to pay.

This is uncomfortable for those who remember when air travel was for the few, but there is little evidence that there is a broad market of people willing and able to pay premium prices to travel on more exclusive planes with edible food. Which isn’t to say that airlines can’t do more business by offering better on-time performance and customer service (like the bigger overhead bins).

During the days before deregulation, where prices were uniformly high and planes were half empty, airlines were willing and able to compete on service and comfort—just as banks with regulated interest rates were reduced to seeking new customers by giving away toasters. Now the rules of the game have changed, with passengers remaining docile—for the moment.