BluSdUp is actually correct, the US did have an entire war plan drawn up to invade Canada. The plans preceded the Arrow but they exist.
https://en.wikipedia.org/wiki/War_Plan_Red
Canada also had plans to repel that invasion and even invade the northern US as part of that defence. There's a lovely documentary about it on youtube... right here.
It is also true that the Arrow program was shut down and destroyed under massive pressure from the US government and our spineless Prime Minister gave into that pressure... and we bought subsonic jets and Bomarc missiles from the US.