What's up with Aeroplan and their flight availability?

I wanted to treat a friend this summer and fly somewhere business/first class with him. I know AC has direct flights to these cities, i.e. Montreal, New York(LGA) or Maui. I checked seat availability and there's plenty of space, hell the flights are almost empty. When I go to the Aeroplan site and enter the dates, I either get "No Flights Available" or the only options offered are the longer, connecting flights. To/from the US, usually the short segment is in J, the longer in Y and at least one segment is on UA and within Canada, it's always a connecting flight either in YEG, YYC, YWG, YYZ. I was even looking at flights to Asia and basically the same scenarios.

If anyone has any Aeroplan booking tips, you're assistance is appreciated.