All this poses a serious challenge to the airlines, who have little idea who is causing the severe disruption they have faced almost every day this week.
Although so far all threats have turned out to be hoaxes, airlines have no choice but take each threat seriously.
“They have a triage system, but follow the same protocols for each until they are absolutely sure there is no threat,” says Marco Chan, a former commercial airline pilot and aviation expert at Kingston University.
“That could involve a mid-air inspection, but definitely a search once the plane has landed.
“Passengers might not even know there is an issue until they are told to disembark. It can cause disruption, but that is a small price to pay when safety is at stake”, he adds.
The sight of sniffer dogs and specialist teams on the tarmac searching for explosives on commercial planes may cause alarm.
So far, the disruption too has been limited to the few thousand passengers who have been directly involved.
Paul Mason, an aviation security expert, says there will be a financial cost to the airline involved, but planes get diverted every day.
“The number can sometimes run to over a hundred planes daily, for things like technical issues, medical emergencies, even the weather,” he adds. “They far outweigh the few which have been diverted due to hoaxes. So airlines are well equipped at dealing with the unexpected.”
It is also unlikely that customers will be able to get refunds, he explains, because these incidents are not the fault of the airlines.
