WASHINGTON (AP) -- If you're flying for the holidays you have lots to think about: what to pack -- and leave behind -- what to wear and how early to get to the airport.Tight security, new technology and airlines' financial woes are making air travel more complicated than ever this Thanksgiving, when many travelers take their one big trip of the year.For the infrequent flyer, there's much to remember even before leaving home. There's the Transportation Security Administration's list of items that can't go into the passenger cabin, such as scissors, small knives and cigarette lighters.Don't forget to wear sensible footwear, like loafers, since you'll probably have to take off your shoes to go through security.Don't carry wrapped presents on the plane -- security may unwrap them to see what's inside. Don't plan on saying goodbye to family or friends at the gate -- people without boarding passes are not allowed past the security check.All the rules mean more opportunities for inexperienced passengers to gum up the works during the busiest travel time of the year. The Air Transport Association, which represents major airlines, predicts 21.7 million people will fly on U.S. airlines over the Thanksgiving travel season between November 19 and November 29, slightly more than the record number that took to the air a year ago. The peak travel time starts Tuesday night.Ron Luczak flies a good deal as marketing director for The Travel Team, a Buffalo, New York-based travel management company. On Veterans Day, he spent an hour and 20 minutes in the security line at Buffalo Niagara International Airport. He was, he said, behind infrequent travelers who didn't know that they had to take off their shoes, belts and jackets -- and forgot to shed other metal -- before walking through the metal detectors."There was mutiny," Luczak said. "People were going to the front of the line saying, 'I'm going to miss my flight,' but so was everyone else."Part of the problem, he said, was that the airlines didn't have enough staff to call the names of people who were about to miss their flights and give them priority.That may be because cash-strapped airlines have been trimming employees to cut costs. From December 2000 to December 2004, the number of airline employees fell 19 percent, from 525,137 to 424,312, according to the Bureau of Transportation Statistics.Travelers Aid International, a nonprofit that assists people in transit, expects to serve a record number of passengers this holiday season. The agency answers questions, gives directions and escorts people, such as children or the elderly, who need help meeting a connecting flight.Travelers Aid President Ray Flynt said his organization is getting more requests at some of the nation's largest airports. For example, it helped 27 percent more people at Chicago's O'Hare International Airport in September than during the same month last year.Airline industry spokesman David Castelveter said the bulk of job cuts are not on the customer service side of the business. And, he said, new technology such as automated document readers at the gates speeds the boarding process."It takes one person to work a flight, whereas in the past it took a few," said Castelveter, ATA spokesman.Airlines are encouraging passengers to buy their tickets on the Internet and print their boarding passes at home, or to use the growing number of self-service kiosks.Kinetics, the NCR Co. subsidiary that sells two-thirds of all airport kiosks in the United States, says the number of self-service stations has climbed by 40 percent annually since 2001.Terri MacKenzie, a 70-year-old nun returning to Chicago, happily selected her seat and printed her boarding pass at United Airlines' self-service kiosk at Reagan Washington National Airport on Monday."I'm delighted to do it this way," MacKenzie said. "It saves loads of time."Still, there's no avoiding the security lines. In an effort to keep them moving quickly, the TSA has issued a press release reminding passengers to leave prohibited items at home and to dress sensibly.Forgetting to leave behind a pen knife can result in a patdown, a stern letter from the government and even a fine.At some airports, there's an added penalty if you don't get through security early enough: you'll miss your flight if you aren't at the gate 30 minutes beforehand.Carl Willis, a ticket agent at American Airlines, said air travelers have had a hard time adjusting to the 30-minute cutoff."A lot of people don't make it," he said.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.