A good question and I wonder how you arrived at this particular one? (I thought- ok someone has been listening to CBC (Canadian monolith television entity). (chuckle).
Yes, right there last night a statement by the urbane news reader. This to the effect that the Mounties were following any possible lead. Then came the "reasuring" statement.
"It could have been a test of the network that is a defence system" or like comment. Now wait with baited breath..... "If they did think the system would not work, they would be disappointed."
Who the "they" were, one can only guess. Still, if any doubt about it, hopefully the cockpit of these aircraft are absolutely proof against entry, by either a kook or homicidal swine.
I've been around as many years as you have (based on your profile page.) Back in the "olden days" in school we actually learned to think.
I remember travelling in airports before 9/11/01 and seeing signs that had to be positioned before the customs screening areas with a message like "Jokes about bombs will be taken seriously."
It seemed to me a reflection on our culture that the signs had to be posted in order to remind adults with enough money and wit to travel internationally, to keep their stupid [funny, ha ha] remarks to themselves.
That was in an age of innocence compared to where we are now. While a hoax phone call is not out of the question, a deliberate attempt to determine what reponse a bomb threat will be met by, is equally plausible.