Don't know if you still need this information (I've been out of touch for a while) but...

Quote
1. Does Canada have an equivalent of a Department of Homeland Security?
I think the agency you're looking for might be CSIS. Check out this site: CSIS

Quote
2. What agency (air force?) monitors Canadian airspace?
Well, I'm pretty sure we employ an Eskimo in Tuktoyaktuk with a pair of binoculars to watch the sky for invading aircraft. Although... come to think of it, do we provide the binoculars or does he? laugh (Just kidding, of course)

ML wave

She was in such a good mood she let all the pedestrians in the crosswalk get to safety before taking off again.
- CC Aiken, The Late Great Lois Lane