Originally Posted by
Guy Betsy
Its not TK that does not want to codeshare with AC but rather AC does not want to codeshare with them. AC would rather codeshare with LH via FRA. So all flights that codeshares with US *A carriers will route you through US gateways instead of the logical choice via Canadian gateways.
It seems that TK has no codeshare in the USA : I can't book IST-JFK-XXX on one itinerary.