Cheek-by-jowl seating and zero elbowroom are to be expected on flights during the summer travel season, but will planes be cramped all year long? And for years to come?
A confluence of factors is making airplanes more crowded, probably for the indefinite future. Traveler demand is strong. Carriers are paring down the number of flights they offer. And the Internet is helping both sides find and fill empty seats.
In some ways, the trend is a win-win for travelers and the airline industry. The same websites that help consumers find the best prices are enabling airlines to fill every last seat - and to steer the industry toward profitability after years of red ink.
But it also means that great deals are harder to come by, overall fares are rising, and many passengers feel packed like sardines, thanks to the airlines' successful tactic of "yield management."
"We have to live with it," says North Carolina resident John McCauley, shrugging his shoulders at a Boston train station as he transitions from an airborne leg of his vacation to continue his trip by rail.
His assessment may be right, some travel experts say. On many routes, the day of the empty middle seat is already going the way of catered hot meals.
The average "load factor," industry jargon for how full each plane is, rose to 77 percent last year, according to the Air Transport Association, which represents the US airline industry.
That's a high that hasn't been reached except during the unusual circumstances of wartime in the 1940s. The storm-ridden summer of 2000 was also noted for full flights. Some major airlines are now running with load factors in the low 80s.
A shrinking number of planes in the sky is just part of the story.
"In the past, the driver of these increased load factors and pricing was reduced capacity. We certainly have that today, [but] it's really the Internet" that's transforming travel, says Kevin Mitchell, chairman of the Business Travel Association in Radnor, Pa. "We will forever see higher load factors."
This doesn't mean the end of all cyclical shifts in supply and demand, analysts say. But as consumers increasingly buy tickets online, airlines have become increasingly proficient at adjusting fares to sell the maximum number of seats at the best possible prices.
In the long run, Mr. Mitchell predicts that the industry will adapt to fuller planes by redesigning seat configurations so that airplanes become more comfortable even when all rows are filled.
But for now, experts are warning passengers to be ready for tight squeezes.
"You're either in the middle seat or next to someone in the middle seat this summer," says David Stempler, president of the Air Travelers Association, a passenger advocacy organization in Potomac, Md.
As airlines have cut back on the number of flights - matching supply ever more closely to demand - many travelers find themselves flying at less-popular times.
"I've taken red-eyes more than ever" recently, says Tim O'Neil, who travels about once a month for his finance job in Salem, N.H.
Airline efforts to return to profitability may finally be bearing fruit after a tide of heavy losses. Last year, the old-line carriers such as Delta and United Airlines narrowed their loss margin to 6.3 percent of revenues, its lowest since 2001. The domestic airline industry as a whole had a loss margin of 3.2 percent in 2005, according to the government's Bureau of Transportation Statistics (BTS).
The improving ledgers are built in part on rising prices, with fares up 9 percent in 2005 from the year before.
This year, fares generally have jumped another 10 to 15 percent, estimates Rob Solomon, the chief executive officer of SideStep Inc., a consumer travel website based in Santa Clara, Calif.
Airlines are flying 4 percent fewer flights, while some 207 million passengers are expected this summer, up 2 million from the year before, Mr. Solomon says, citing Air Transport Association figures.
Although airlines are doing better financially, their lack of profits suggests an industry in which cost-conscious consumers still have lots of leverage.
Even after last year's rise in fares, a BTS index of travel prices had merely climbed back to the level it had reached in 2000, before a recession and the 9/11 terrorist attacks dented demand.
Despite rising fuel prices, fares haven't kept pace with inflation during the past decade.
The Internet has given consumers sophisticated shopping tools. "It definitely is revolutionizing the consumer experience," says Solomon.
The site he runs, SideStep, is a case in point. Users plug in their desired dates and destinations, and within seconds the website scans other online travel sites for the best available prices.
To make the best of this year's crowded airports, experts offer the following tips:
• Book early. It's not too soon to buy for the December holidays.
• Arrive early. "If you don't make your flight for any reason, there's not that much room on the next flight," Mr. Stempler warns.
• Be organized. Putting change and other metal objects in a zip-lock bag can help speed you and other passengers through the security check. Consider printing your boarding pass on a home computer the night before you leave.
• Hunt for bargains on lodging and rental cars in advance, too. Rising room rates mean that hotels may outweigh air fares in vacation budgets.
"You go back 10 years ago, that was certainly the opposite" situation, says Randy Peterson, editor of InsideFlyer magazine.