An airport security breach and the response involving the Air Canada flight appears to be a tale of two lapses — one of security, the other concerning judgment, according to airport security experts.

Officials at Toronto's Pearson International Airport apologized on Thursday after a man who managed to elude security screening boarded a flight to Brazil. As questions swirled about how that breach may have occurred, the matter of why Flight AC 090 was asked to keep flying and then turn back to Toronto is the real curiosity, analysts say.

By the time the pilot received a directive to turn back, the aircraft had already been several hours en route to Sao Paulo.

"That's the most puzzling thing to me," said Jeff Price, an associate professor of aviation at the Metropolitan State University of Denver. "Why did they fly all the way back? That's unusual."

The typical response to a security incident on a flight is to quickly ground the plane at the nearest runway to neutralize the situation, he said.

A heavy security and police presence greeted the plane when it returned to Pearson Airport. (Submitted by Chantal Vallee)

Transport Canada ordered the Toronto-to-Sao Paulo flight to backtrack to Pearson about four hours after its midnight departure. By 6:30 a.m., police in Toronto apprehended the passenger. He was released after authorities determined there was "no criminality involved," according to Peel Regional Police.

'Governments are famous for overreacting'

CBC News has learned that the passenger had connected from another flight and left the airport for a cigarette. But when he returned, he reached his gate through a door reserved for airport staff.

Nick Casale, a New York-based terrorism and transportation security consultant, said Transport Canada's demand that the pilot take the "extraordinary step" to turn around seemed counter-intuitive in this case.

"It makes no sense," he said. "If there is such a significant issue, if the pilot believes there is a breach of security or a real threat, he should land at the nearest airport, even a military airport, any airport that the plane is capable of landing at."

Although Casale said he was reluctant to criticize what a government might consider to be security protocol, he argued that bringing the plane home "would just allow the threat to be present" instead of resolving it as soon as possible.

You need to take decision on the basis of risk, not just blindly follow procedure because somebody says you need to shut down the terminal or pull flights back. - source

"Governments are famous for overreacting, and it's almost that they overreact when they should under-react, and under-react when they should be overreacting," he said.

Contacted by CBC News and asked whether recalling aircraft to airports was a common security measure or part of protocol, Transport Canada said it could not go into detail.

"For security reasons, we cannot disclose the reasons behind this decision," a statement said.

For logistical, cost and safety reasons, it's not a decision that should have been taken lightly, however.

A costly decision

Many of the passengers were reportedly headed to Brazil with tickets for the FIFA World Cup. Owing to the delays, one passenger told CBC News, many ended up missing the England versus Uruguay match.

The breach grounded flights at Pearson while a search was underway for the person who bypassed the checkpoints.

This photo, sent to CBC News by a passenger on the flight, shows passengers in a waiting room after their flight to Brazil was turned back early Thursday. (Submitted by Olivier Cullen)

"Obviously, calling the flight back is a very expensive decision," said Rafi Ron, former director of security at Tel Aviv's Ben Gurion International Airport.

"I understand many of the passengers were flying to watch the game and probably spent thousands of dollars as a result of that decision," he said.

But a shutdown of the terminal at any major airport could cost "dozens of millions of dollars" because of flight cancellations and delays, he said.

Ron, who was hired to bolster Boston Logan Airport's security immediately after the Sept. 11 attacks, said security consultants have begun focusing on training personnel toward a "risk-based approach," in which "common sense overrules procedure" to avoid errors.

"A lot of it has to do with really bad decision making," he said. "You need to take decisions on the basis of risk, not just blindly follow procedure because somebody says you need to shut down the terminal or pull flights back. You don't just do it every time, no matter what the cost is. That is an unintelligent policy."

He said that in most cases, he could imagine flights proceeding to their destination so long as it could be determined within reason that the offending passenger had no malicious intent. Any issues over identification or credentials could be examined upon arrival.

Stupidity and 'sensation seeking'

Price said a common, innocent mistake at airports is for a person to be flagged for secondary screening, then wander off, or enter through an exit lane.

"Those situations are far more common than for someone to miss the entire checkpoint," he said, adding that airport officials would likely re-evaluate Pearson's checkpoint design "to see if there are any areas where people could just bypass it."

As for why someone might intentionally skip a screening area?

A Canada Border Services Agency officer performs a secondary examination demonstration at Pearson Airport in Toronto. (Aaron Vincent Elkaim/Canadian Press)

Richard Bloom, director of terror intelligence and security studies at Arizona's Embry-Riddle Aeronautical University, said a common reason is simple mischief and "sensation seeking" rather than plotting an attack,

"It's someone thinking, 'Let me see if I can do that, even though it’s a stupid decision.' But at the moment, it seemed like a good idea," he said. "It could be someone making a stupid decision to knock some time off the process of getting to the actual boarding area."

The Greater Toronto Airport Authority said it will be conducting a comprehensive internal assessment to look into what went wrong.