I can't comment on the number, but tied to the number of Auroras is also the question of the status of the north warning system, and also brings up issues of cybersecurity, etc. Fixating on the number is a bit like looking through a straw: you're narrowing your lens and missing some of the other implications. I would certainly defer to the Department of National Defence on whether or not they think they have enough planes. The other aspect is the number of funded flying hours. You can have all the planes in the world, but if you don't have enough money to send them up there to do the surveillance, that's also a problem. That's something that is often the last to be considered in a budget.
On November 1st, 2016. See this statement in context.