Travelers who expected lines at airport security checkpoints on Friday were pleasantly surprised to find that tighter security didn't lead to longer delays.

The last week of the year is traditionally one of the busiest for air travel. Airlines had expected 17 percent fewer travelers than last year at this time; instead, passenger volumes were down only 11 percent, according to the Washington-based Air Transport Association's chief economist David Sweringa.

Several major carriers said planes were 90 percent full at their peak — about as full as the planes ever get. 

Nevertheless, the industry is operating with 16 percent fewer seats available, due to cuts made after Sept. 11.

"It has been better than we would have thought four to six weeks ago," said John Tague, chief executive officer of American Trans Air, the nation's 10th-largest carrier and one of a handful of low-cost, low-fare airlines that have outperformed the rest of the industry lately. 

The largest carriers are not likely to report profits until next summer, at the earliest, because they continue to lure passengers with extremely cheap fares, said Ray Neidl, airline analyst at ABN Amro.

Security, though efficient, was thorough, with many airports adding shoe x-rays in the wake of this week's attempted destruction of a jet with an explosive hidden in shoes. Delays at checkpoints ranged from a couple of minutes to a couple of hours.

At Sky Harbor International Airport in Phoenix, a 78-year-old woman with a pacemaker was hand-frisked. In New York's LaGuardia Airport, a middle-aged teacher was asked to finish her coffee by security personnel concerned something could be hidden inside the cup.

Nancy Franger of Elkhart, Ind. had her nail clippers and files confiscated at O'Hare as she headed to Colorado for a ski trip — but she didn't mind.

"I'm glad they caught that stuff," Franger said.

At Dallas-Fort Worth Airport, traveler Jim Hutchinson said he didn't mind removing his cowboy hat, boots and belt buckle as part of the security screening.

"I'm kind of shocked things were so lax before," Hutchinson said. "It's crowded. Check-in takes a few minutes. What's the big deal?"

Travelers who arrived early expecting lines, however, added to large crowds. Crowds were everywhere at Denver International Airport — from check-in to baggage claim areas — but waits were typically no more than 20 minutes.

"Passengers are patient, and workers are just doing a great job moving people through the lines," said Mike Bowers, vice president of stations operations for Frontier Airlines. "Believe it or not, it's been a good couple of weeks."

In the days before and after Christmas, check-in lines were often backed up, and boarding gates were crowded with passengers who arrived early and then found check-in and security screening took less time than expected, said Matt Buckley, Southwest Airline's senior director of ground operations.

"It's like a snake swallowing an elephant, at times," he said.

The Associated Press contributed to this report.