Obviously it doesn't happen as often, but it does happen. I don't have specific command statistics at my fingertips, but I know from personal experience, having worked on the strategic joint staff last year, that there have been occasions where we have sent Canadian Forces F-18s into American airspace in response to an air incident. It does happen. Obviously, the United States has more fighter resources than we do. The commander of NORAD uses all the fighters that he has at his disposal, both Canadian and U.S., to make the best decisions.
I think when there is a threat stream or we have indications and warnings of an event, then the commander of NORAD repositions the aircraft to be ready to respond to those events. For air incidents that occur in Canadian and American airspace in civil aircraft, as you can imagine, there's very little notice involved with those kinds of incidents, so we don't have the opportunity to forward or position aircraft.
Given the size of our country and the resources that we have for defence, I don't think we'd ever be in a position where we would always be able to scramble an aircraft to intercept another aircraft anywhere in Canada. I don't think that's realistic. That's why the NORAD agreement works so well for us because we are able to help the Americans out and they're able to help us out, but in a way that respects each other's sovereignty.