Originally Posted by
D582
Canada-US fares are subject to GST if the fare orgin is Canada. AIF is taxed in the province if is incurred in.
It is based on fare origin, not point of sale.
Fair enough. Since OP's itinerary was YTZ-BOS round trip, presumably it was subject to GST, and then the question reverts to whether OP will be able to get the GST back.