Travelers in the midst of another holiday season of shuffling shoeless through seemingly interminable airport security lines may find it difficult to imagine a future where screenings are not only speedy but thorough.
But Kenneth Dunlap, director of security at the International Air Transport Association, a global airline lobbying group, suggested just such a situation, seemingly straight out of the 1990 Arnold Schwarzenegger film “Total Recall.” In it, travelers would stop only briefly to identify themselves before entering a tunnel where machines would screen them for metals, explosives and other banned items as they walked through.
Such a vision may remain just that, a relic from a 20-year-old movie. But with global air traffic approaching 2.8 billion passengers a year and growing steadily about 5 percent a year, industry executives and security experts say a fundamental rethinking of today’s security checkpoints is inevitable.
What is less clear, however, is when — and to what degree — technology,regulationand public acceptance may come together to create nuisance-free security screening worldwide. Moreover, critics of the current system, including aviation security consultants, airport executives and passenger advocacy groups, say the innovations may not be any more likely to thwart a determined terrorist than today’s systems.
As to the air industry group’s idea, “it is a concept that has been growing in popularity,” said Norman Shanks, an aviation security and airport management consultant near London. “Technically, it is feasible. But practically, it’s fraught with problems.”
There is little disagreement over the need for vigilance at airports. But after the British authorities uncovered a plot in 2006 to bomb passenger planes bound for the United States using liquid explosives and an attempt in 2009 by a Nigerian man to ignite a bomb hidden in his underwear, new security measures have proliferated, stretching checkpoint wait times.
According to the airline group, airport checkpoints globally cleared an average of just 149 people an hour in 2011, down from 220 people an hour five years ago. At peak travel periods like Christmas, the number of passengers cleared has slowed to as few as 60 an hour at certain airports.
Many of the technologies that would be needed to drive a reliable walk-through security checkpoint are still laboratory prototypes. Others, like full-body scanners, biometric identification and various liquid and conventional explosives detection systems and even infrared lie detectors, are already in use or being tested in airports. But public concerns about privacy and the potential health effects of repeated exposure to X-rays, for instance, have led many governments to tread carefully.
“With any new technology, you get a certain amount of ‘What is this about?’ ” Janet Napolitano, the Homeland Security secretary, said in an interview. She said that the 500 or so body scanners in place at more than 100 airports in the United States had recently been equipped with software that generated a generic outline of passengers to protect their privacy. And while she played down the potential health risks linked to certain types of body scanners that use X-ray technologies, she acknowledged that “there is always a certain reticence when radiation is involved.”
To many security experts, however, improving both waiting times and security has less to do with rolling out sophisticated new machines and more with gathering information about passengers before they even arrive at the airport.
In the United States, the Transportation Security Administration has begun to shift to a more “risk-based” method of screening airline passengers, with the premise that the overwhelming majority of travelers pose no threat, yet must still be screened.
The first small step in this direction is a new program called PreCheck. Also known as the “trusted traveler program,” it provides airport security agents with the kind of information airlines routinely collect and store on their frequent fliers, including how they paid for their tickets, the history of their past flights and personal information like their home addresses.
The T.S.A. started the program in October by working with Delta Air Lines and American Airlines. Both airlines were asked to select some of their elite travelers and ask them whether they wanted to enroll in PreCheck, which currently offers faster screenings at a handful of airports. The agency plans to expand the program, which has 85,000 members, to other airports and other airlines.
“What we are trying to do is find that needle in the haystack,” said John S. Pistole, the head of the T.S.A. “If we can reduce that haystack, it can help us. We have to have a starting point someplace. The intelligence tells us a number of things, but the great likelihood is that a very frequent flier is not going to be a terrorist.”
Mr. Dunlap, of the airline trade group, said PreCheck was the only program of its kind. It was modeled on other programs that expedite clearance through customs and immigration checkpoints in more than 25 countries worldwide, including GlobalEntry in the United States, Privium in the Netherlands and Nexus in Canada, he said.
The trade group estimated that 30 percent of all air passengers now had sufficient data records and willingness to take part in a trusted traveler program. Not surprisingly, those passengers are generally business travelers who average about five airline trips every 18 months.
The T.S.A. took another small step toward speeding up the security process in September when it stopped requiring most children under 12 to take off their shoes while going through the checkpoints. It also said it had modified its procedures to reduce the likelihood that children would be subjected to a pat-down if they set off the metal detector.
The agency has also begun a test at some airports of exempting airline pilots, a low-risk group by definition, from going through security. (Flight attendants, though, must still follow the same drill as regular passengers.) Uniformed members of the military can keep their boots on, though they, too, still must go through security.
Critics argue that while such programs help ease the pain for millions of air passengers, they are not foolproof.
“I don’t believe that we can rely on people who have a clean history, because that can be abused,” said Mr. Shanks, the consultant in London. “Either by a terrorist sleeper who builds up a long travel record to escape suspicion, or by some innocent person who is forced to carry something through because their family is being held hostage by terrorists.”
Mr. Shanks and others argued that training airport security agents in techniques like behavior analysis would go a long way toward identifying travelers with possible ill intent.
“It is a process which is reasonably noninvasive and could be tied into the system to select people to go into a particular lane” for enhanced screening, he said.
A growing number of airports have started to do that. The T.S.A., for example, has trained 3,000 of its agents in techniques meant to detect suspicious behavior by passengers. The agency says this has resulted in the arrest of over 2,000 people — although those were all for criminal conduct, not suspicion of terrorism. Still, civil liberties advocates question whether that might eventually lead to the profiling of passengers based on their ethnicity or race and might violate their civil rights.
The airline group estimated that 3 to 9 percent of passengers are now singled out for enhanced screening, chosen on the basis of behavioral analysis, government watch-list data or at random. The group has called for the creation of separate checkpoint lanes for processing those higher-risk passengers. If this was combined with a known-traveler lane, the group estimated, average checkpoint waiting times could be reduced about 30 percent within two years.
In the meantime, governments and industry are seeking other ways to reduce the inconvenience for passengers. The European Union and Australia, for example, have vowed to eliminate all restrictions on carrying liquids, gels and aerosols in hand luggage beginning in 2013 by deploying new X-ray scanners that can detect liquid explosives. The T.S.A. has said the liquid scanners do not yet meet its reliability standards, though Ms. Napolitano said the United States “would like to work toward” an alignment of those rules.
Such international disagreement, security experts said, was evidence of the obstacles to making even small changes in screening procedures.
“In the end, changing a checkpoint is a political process, not a technological process,” Mr. Dunlap said. “Getting the changes to the laws needed and getting regulators to go along with it is the real challenge.”