If this is coming...https://www.ctvnews.ca/business/air-canada-ceo-says-he-is-glad-bombardier-challenged-aircraft-duopoly-1.3400510#
being an American airline I would start putting small orders in right now with large order options to give me sometime to find a way around the new tax regime.
Or it might get cheaper for the Americans to just fly to Canada and finish their trip on a Canadian airline.