The high-speed line would likely connect almost directly with Pearson and directly with Dorval. The Ottawa airport would also be relatively close either by transitway or with a rail connection. Jean-Lesage airport in Quebec is also very close to existing rail lines and could easily be served with HSR.
My point is, while US connections are definitely important, connections to their airports aren't necessarily as important. With much of the air traffic cleared up between Montreal, Ottawa, and Toronto, and with improved access to these airports, it would then become possible for airlines to run more economical direct services to overseas destinations. This is especially true of Montreal-Ottawa who would share both of their airports. People living in Southwestern Ontario, or on the Niagara peninsula would also have greatly improved access to Pearson, making such flights. However, it would help if Air Canada weren't so bloody expensive. Depending on the time it takes to clear the US border on a high speed train, it may be more worthwhile for US bound passengers to just cross the border and use US airports for domestic trips, but I don't hold out much hope for the border becoming faster any time soon. My greatest fear is that international border crossings for anyone not in a motor vehicle will become more and more like airport security, negating any time benefit to actually using the train.
Some on here argue that it would be worth it to harmonize our trade at the price of our sovereignty. However, one only has to take a look at the recent economic collapse to see how disaterous it could be for Canada if US interests fully controlled our economy and our government lessened its scruity on financial institutions to become more like the US. In any US-Canada economic merger scenario, Canada would almost always become exploited.
