Originally Posted by
YOWkid
GST/HST is only charged on the AIF for international tickets.
I don't think the US qualifies as "international" for that purpose. My two data points today are (1) AC charges GST on Southwestern flight pass (only good for Canada-US flights) and (2) GST is charged on base fares for a few TB itineraries I looked up, e.g. YYC-SFO, YYZ-LGA.
Although in the opposite direction, e.g. SFO-YYC round trip, GST is charged only on the AIF. So perhaps if the POS is in the US, GST is not charged on TB, but for originating in Canada, it appears to be.