Here are a few facts about how such situations are handled:
How frequently do airlines have to contend with bomb threats?
Not very often, according to industry observers. Edward McKeogh, President of Canadian Aviation Safety Consultants, says it's not unheard of for airlines to go a full year without fielding a threat of real substance. McKeogh said the major airlines tend to be the most common targets.
How do airlines typically respond when threats do occur?
While individual protocols may vary among airlines, McKeogh said the basic approach is the same — every threat must be taken seriously.
"As soon as they find out about a threat of this nature, they relay it to the flight in question, or sometimes all flights that are airborne, and those flights will then divert to the nearest suitable airport," he said. This wasn't always the case, however.
Jock Williams, a retired flight safety officer with Transport Canada, said 9/11 brought about significant changes in the way even idle threats are handled. Airlines, he said, used to have much more discretion to assess individual situations.
"In the past, they've made an educated guess and maybe said, 'No, we won't do anything about this,'" he said. "I don't think you're going to see much 'No, we won't do anything about it' anymore."
What's the economic impact on the airline?
McKeogh said each diversion is an expensive proposition. By the time an airline reroutes the flight, deplanes the passengers, ensures they're taken care of at the alternate airport, inspects the aircraft and then resumes the original course, he said the bill can easily equal tens of thousands of dollars.
If someone is caught making a threat, what legal consequences can they expect?
Christine Duhaime, a counter-terrorism lawyer with Duhaime Law, said even an unsubstantiated threat can trigger very serious penalties. Even a hoax can result in jail time, she said, since the perpetrator's actions trigger real practical and economic consequences. She said sending threats would be seen as consistent with terrorist efforts and tactics to attack critical infrastructure.
"Those attacks are either going to be real, or will surface as these did, with threats for which no real physical attack occurs," Duhaime said in an email. "They are attacks nonetheless, because they are intended to cause economic harm to the private sector, debilitate critical infrastructure and drive up costs for counter-terrorism programs in the West."
Williams said the Canadian government's recent introduction of tougher anti-terrorism laws suggests anyone behind such threats shouldn't expect to get off lightly.
"This is a very serious federal, criminal offence and I think will be treated very harshly if and when they catch the individual," he said.
So what do we know about the current string of threats?
Very little. The RCMP did not return calls seeking request for comment. WestJet spokesman Robert Palmer said the rash of threats has triggered "rumours and speculation" that the airline is not willing to comment on.
"We will continue to work closely with law enforcement to find those responsible. Safety remains our top priority and we will continue to be vigilant to keep our guests and our crews safe," he said.