Originally Posted by
xliioper
Yes, UA could potentially sell an AC fare on intra-CA segments (UA does not have their own fare filings on intra-CA routes, so in addition to being CA metal, it would need to be a CA fare and CA coded flight), but it's not something you can do on website. This thread has some more backstory --
Booking partner only cash flights on United.com / app
Of course you can; it just needs to be part of a larger itinerary.
I just priced out AUS-YYT / YYT-YZF / YZF-AUS on United.com. It came up with two UA flight numbers for AUS-YYZ-YYT (both AC codeshares, obviously); AC flight numbers for YYT-YYZ-YZF, and then an AC flight number for YZF-YVR followed by UA codes (on UA metal) to DEN and AUS. It appears to have broken the fare at YVR (I get four fare components).
Bottom line: there is no cabotage issue at play here. Whatever is causing OP to have issues booking this itinerary, it has nothing to do with illegal cabotage.