I had hoped to book an Aeroplan routing, but had to confirm couple of details before booking. By the time I went to book a few hours later, two of the three routes were unavailable.

Is there any rhyme or reason to whether or when Aeroplan might open up additional seating? The flights are still wide open.

Also, does Aeroplan have the same 24 hour grace period that Air Canada has? Because I wasn't sure, I didn't want to book till I had other details confirmed.