It's not as bad as you think. These days to go pretty much anywhere from Ottawa (save a few US, international and seasonal Caribbean destinations) you have to connect through Toronto or Montreal. It would not make too much of a difference. However, the few remaining flights could be consolidated at either Toronto or Montreal. The airlines would actually like it because it lets them use larger, more efficient aircraft. Though, I'll admit that service wise its a bit of a step backwards in time to when all trans-atlantic flights had to land at a port of entry. Maybe, Mirabel can come into play again. They can finally achieve their dream of consolidating air traffic in Ottawa and Montreal at Mirabel.