Originally Posted by jinglish

Sorry if this is the wrong board, but Travel Tools didn't seem appropriate since I think this is a problem not with ITA but with the relevant fare rules themselves.

I'm trying to book a one-way from SEA to TPE, and fares are much better for directs from YVR than SEA, including a pretty good economy fare on CI, but I'd like to tack on a SEA-YVR segment so I actually have some IRROPS protection and can avoid paying extra YVR taxes and fees. This should be doable, and CI and AC have an interline agreement, but while Matrix shows me the itinerary I want, the TPE-YVR segment is on a full Y fare. I'm poring over the two fare rules and don't quite understand why R won't work. Here are the combinability terms for Y:And for R:

I'm not the most familiar with fare rule terminology, so I'm not quite seeing why this end-on-end ticketing won't work with the CI R fare. Does the "combinations are for carrier CI" mean it can only be ticketed end-on-end with other CI-marketed fares?