ATLANTA, USA

As the travel season picks up, many passengers this spring are about to have their first encounter with airport security measures stepped up after Christmas, when a man was accused of trying to blow up a US jetliner using explosives hidden in his underwear.

With the extra measures rolling out, security lines are expected to grow. Airlines, meanwhile, worry the government will require them to pay to maintain the beefed-up security checkpoints.

The Obama administration is committing tens of millions of dollars to deploy more state-of-the-art screening equipment, and it is tightening enforcement of some older security measures.

For example:

*There are now 44 full-image body scanners at 21 US airports, a 10 per cent increase from before Christmas. Chicago’s O’Hare and Boston’s Logan are the latest airports to add these. Nearly 1,000 scanners will be in use nationwide by the end of next year.

*The use of “swabs,” or Explosive Trace Detection machines, has been expanded in recent weeks. Security agents are now more frequently roaming boarding areas and security lines with portable machines, which can detect traces of explosives after a cotton swab is applied to hands or luggage.

*The Transportation Security Administration has sought to make screening less predictable. At some airports, passengers are asked to choose between a body scan or a pat down. A passenger who refuses a 30-second body scan may receive a two- to four-minute manual pat down.

A passenger might proceed to their plane after clearing just one form of screening. Or they could run the gamut like software executive Bob Thomas did on a recent flight departing from Atlanta’s Hartsfield-Jackson airport.

A gum wrapper made of aluminum foil in Thomas’ pocket set off a metal detector. After that, he went into a cylindrical machine 6-foot-wide (1.8-meter-wide) by more than 8-foot-high (2.5-meter-high) to have his body image taken. Next came the hand swab. Lastly, he sat down and lifted his legs for a pat down by an airport screener. All clear.

For the former Marine officer, the extra few minutes were “a big waste of my time.” But he understands the agents’ predicament. “They don’t know” which passenger is a potential threat, he said.

Fliers say they are understanding of the new measures, but nevertheless agitated by them.

Merle Thompson, a 77-year-old retired college professor from Virginia, recently got a taste of the enhanced screening measures.

Because her steel replacement knee often sets off the walk-through metal detectors, agents usually screen her with a hand wand. But that wasn’t enough ahead of a recent flight to San Francisco from Washington.

“They patted me down,” Thompson said. “Which I found humorous and ridiculous.”

In a recent survey of more than 3,200 US air travelers by travel Web site TripAdvisor, 39 per cent cited long security lines as the most annoying part of being at an airport.

Security lines subsided in the slower winter months. But airlines are starting to see increased demand in March asoesn’t believe the scanners will “significantly” increase the wait on security lines.

Some airlines advise passengers to arrive 75 minutes ahead of a domestic flight and up to three hours ahead of an international flight.

The increasing use of body-imaging technology makes some fliers uneasy. In addition to finding hidden explosives and weapons, the scanners reveal more bodily detail than passengers might prefer.

Sanjeev Verma, a technology entrepreneur from Massachusetts, was at Logan International in Boston just a day after the airport began using three new scanners. He called them “intrusive,” even though he had not yet been through one.

Some people find the images too revealing. The issue is sure to linger as hundreds more scanners appear this year at airports such as Fort Lauderdale/Hollywood International and Charlotte Douglas International.

But security isn’t the only bane of travelers. They’re also concerned about pocketbook and comfort issues like fees for checked baggage and limited legroom on the plane. And Verma says he’s more annoyed by the limits on liquids like shampoo or toothpaste.

The airlines, buoyed by a pick-up in passenger traffic, worry about eventually bearing the costs of more security. That could impact passengers, who already pay a smorgasbord of taxes and fees when they buy a ticket, said David Castelveter of the Air Transport Association, an industry group that represents US airlines.

Tickets include a security fee of US$2.50 for each individual flight. The fee is capped at US$5 in each direction. That fee could be raised or a new one added on, though TSA hasn’t made a request to do so.

For airports, the high cost and lack of space can hinder efforts to expand scanner use.

The Minneapolis-St. Paul airport is remodeling two checkpoints at its expense to install new baggage-screening equipment, a move that also would make room for body scanners. But if TSA wants scanners at other checkpoints, it’s unclear who will pay for any remodeling, airport spokesman Patrick Hogan said.

The government is installing 450 scanners this year. At an average of US$150,000 each, that’s US$67.5 million just for the machines. President Barack Obama’s fiscal year 2011 budget requests US$88 million for another 500 units.

TSA is also using US$15 million to buy 400 more portable explosive detection machines this year. Obama has requested US$39 million to buy an additional 800 machines in fiscal 2011.

In addition, Obama has promised to put more air marshals on flights. His fiscal 2011 budget includes US$85 million “for increased federal air marshals on international flight coverage.”

In this March 8, 2010 photo, Sanjeev Verma (right) of Lincoln, Massachusetts. (Photo: AP)