Probably from the old
Norad base shut down when over the horizon radar replaced the DEW line.
How many countries had a moose on the tail of their aircraft?
During the Cold War it was quite often these guys were scrambled to intercept Soviet bombers approaching our borders. Since those bombers were almost certainly headed towards the U.S., Canadians often wondered "Shouldn't the Americans be paying fo this?" After all, what was there to bomb in Canada?
Now you have an American president calling us defence freeloaders, but we know who the freeloaders are.