When an attempt to set a transatlantic jetliner aflame above Detroit was foiled on Friday, an old debate was reignited on the ground.
The airline industry and experts who study it have been locking horns for years with the U.S. government agency in charge of transportation security over how best to tackle the problem of terrorism in the air.
As restrictions on U.S.-bound international flights have escalated to unprecedented heights - passengers are forbidden to hold anything on their laps or to leave their seats during the last hour in the air - many experts believe regulators have taken a backward approach to the issue. They argue that pouring money into additional preboarding inconveniences - including the kind of invasive searches that may have prevented the Detroit incident - will never eliminate the risk that a terrorist will bring down an airplane.
"We really need to consider the alternative path, which is spending those billions on intelligence work and basic police work directed at places and individuals who would do harm to the [airline]industry," said Robert Mann, an aviation consultant based in Port Washington, N.Y.
"There was a tip from the father of the individual who is alleged to have put together the Detroit plot. We did nothing. And we could have kept the individual far, far away from the airport," he said, adding: "Frankly, airports are not a good last line of defence."
Bruce Schneier is a security consultant and author who has become a well-known critic of the airport screening measures put in place by the U.S. Transportation Security Administration since Sept. 11, 2001. He has waged an ongoing campaign of small-scale stunts - including the creation and successful use of fake boarding passes - to illustrate his arguments. They centre around the notion that policy makers wrongly prioritize reactive, visible measures that appear to increase security in airports - such as repeatedly checking identification or limiting passenger movement during the last hour of flight - over less visible measures, like beefing up foreign intelligence, that would be more effective in stopping terrorism.
"Right now we are engaged in this huge show, this huge piece of security theatre," he said. "We're engaging in magical thinking in that by defending against what the terrorist happened to do last time, we think we'll make ourselves secure. It's like saying the terrorist wore a green shirt, so no more green shirts," he said in an interview.
"These measures are only effective if we happen to guess what the next terrorists are planning. If we concentrate airport security on screening shoes and confiscating liquids, and the terrorists hide explosives in their brassiere and use solids, we've wasted our money," Mr. Schneier wrote in a recent self-published essay. "It's not the target and the tactics of the last attack that are important, but the next attack."
The goal of air travel security in the future, the experts agree, should be to prevent terrorists from ever reaching the airport.
"We need to fight them not at the airport, not in an aircraft, but in places where these would-be harm-doers are developing their ideas and fermenting their plans," Mr. Mann said. "We're focused on fighting the last battle, not the next one," he said, adding: "It seems like we can only go in two directions here."
In the long term, continuing on the same course that began in the wake of the terrorist attacks of Sept. 11, 2001, is simply not feasible for the industry or its customers, they argue.
"If we strip-search passengers, if we ask them not to carry anything on [to the aircraft] it would increase safety. But the question we need to ask is would that extra level of safety be desirable," said Bijan Vasigh, a professor of economics and finance at Embry-Riddle Aeronautical University in Daytona Beach, Fla., and managing director of Aviation Consulting Group.
"If everyone goes naked, there is no risk. But it is not desirable. The margin of improvement … is not as beneficial as the margin of cost."
Airlines have already paid significantly for the passenger inconveniences and delays caused by the onset of new security regulations since 2001. Mr. Mann said the industry has been charting a dramatic surge in the use of private jets and smaller aircraft as companies opt for more convenient, reliable and less time-consuming modes of travel.
An increase in security restrictions at large airports is predicted to further deepen the pain commercial airlines are feeling.
"What it will do for sure is deter travel," Mr. Mann said.