WASHINGTON — Airline passengers, who already must remove their shoes, take off their coats and carry only small bottles of liquids, now have a new directive at airport checkpoints: Pack neatly.

In anticipation of the most popular holiday for travel in the U.S., the Transportation Security Administration today launches a campaign urging travelers to eliminate clutter in carry-on bags. Pack in layers. Keep items neat.

The messy traveler could spend more time in line if their carry-on is cluttered because they are much more likely to be pulled aside and hand-searched, TSA spokeswoman Ellen Howe says. The added search could add up to three minutes to a traveler's time in the security line, she says.

"Whether or not the (TSA) campaign is effective, the effort is certainly welcome because with 27 million-plus people scheduled to fly over Thanksgiving, every effort to speed up the security checkpoint will help," says David Casteleveter, spokesman for the Air Transport Association, the major airline trade group.

Some of those traveling may not be familiar with the rules in place at security checkpoints. "This is one of the holidays where you're dealing with the less-savvy traveler," Casteleveter says.

The neat-and-tidy exhortation, dubbed SimpliFLY by the TSA, is the latest effort to prepare people for a holiday travel period that is expected to draw record crowds into jam-packed airplanes flying through congested airspace.

The busiest travel days this week will be Wednesday — the day before Thanksgiving — and the Sunday and Monday after the holiday, when airlines expect more than 2.5 million travelers a day, a 20 percent hike above normal levels, according to the Air Transport Association.

As airports urge travelers to arrive extra early and the government creates new airplane routes, the TSA is pointing out that neater packing can expedite checkpoint lines.

"If you eliminate clutter, it helps us get a cleaner look at the contents of a bag" on checkpoint X-ray machines, Howe says. The faster that screeners can figure out what's inside a bag, the quicker they can clear it.

"You can help make your experience better if you come prepared," Howe says.

Kevin Mitchell, chairman of the Business Travel Coalition, applauds the TSA's effort, but says he's not "real optimistic" it will help expedite security lines. "The message is a pretty sophisticated one, and it's a lot for the average person who is traveling for the first time in months to remember," Mitchell says.

The TSA has sent airports and airlines posters and a 60-second video in which a female narrator advises people packing bags: "Think layers. One layer of clothes. One layer of electronics." The video, set to a catchy doo-wop-sounding vocal riff, will be played on checkpoint screens that broadcast security announcements.

Airports also are going beyond trying to speed up lines and are preparing for stranded passengers, says Eileen Denne of the Airports Council International. Atlanta's Hartsfield-Jackson International Airport recently bought four new buses to retrieve travelers from planes stuck on the tarmac, Denne says.

Checkpoint tips

- Eliminate excess clutter in carry-on bags.

- Pack clothing in one layer of your bag, electronics in another.

- Put liquids and gels in a single one-quart, clear plastic, zip-top bag.

- Remove shoes and coats at checkpoints.

Source: TSA