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:
FARES MAY BE COMBINED ON A HALF ROUND TRIP BASIS WITH ANY
FARE FOR ANY CARRIER IN ANY RULE AND TARIFF TO FORM
SINGLE/DOUBLE OPEN JAWS/ROUND TRIPS/CIRCLE TRIPS.
END-ON-END PERMITTED. SIDE TRIPS PERMITTED WITH NO
RESTRICTIONS. VALIDATE ALL FARE COMPONENTS. TRAVEL MUST
BE VIA POINT OF COMBINATION.
ADD-ON CONSTRUCTION IS ADDRESSED IN MISCELLANEOUS
PROVISIONS - CATEGORY 23.
And for R:
SINGLE/DOUBLE OPEN JAWS/ROUND TRIPS/CIRCLE TRIPS NOT
PERMITTED.
APPLICABLE ADD-ON CONSTRUCTION IS ADDRESSED IN
MISCELLANEOUS PROVISIONS - CATEGORY 23.
END-ON-END
END-ON-END COMBINATIONS PERMITTED WITH NORMAL OR SPECIAL
FARES. VALIDATE ALL FARE COMPONENTS. SIDE TRIPS
PERMITTED.
END-ON-END NOTE -
THE MOST RESTRICTIVE CONDITIONS MUST BE APPLIED
FOR THE ENTIRE JOURNEY.
PROVIDED -
COMBINATIONS ARE FOR CARRIER CI IN ANY RULE IN TARIFF
CPR - BETWEEN THE UNITED STATES-CANADA
DFR - WITHIN THE UNITED STATES
IPRPG - WITHIN AREA 3-INTERNATIONAL
IPRTPFD - WITHIN AREA 3-DOMESTIC
IPRW - BETWEEN THE USA/CANADA-AREA 1
IPRWD - WITHIN THE WESTERN HEMISPHERE-DOMESTIC
IPRWI - WITHIN THE WESTERN HEMISPHERE-INTERNATIONAL.
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?