Originally Posted by ashill

Unfortunately, US makes it very difficult to tell as they (unlike every other airline I know of) say "operated by US Airways" even for US/US* flights. And their eticket receipts just say "Flight #XXX operated by US Airways", which makes it very difficult since every US flight has a corresponding AA codeshare with the same number and vice versa. You just have to know that usairways.com only sells US-marketed flights. But Orbitz can sell AA-marketed flights on a US ticket, so hopefully the Orbitz receipt makes it clear. Rather a mess.

I hadn't noted that alaskaair.com says AA ticket stock is required. That's weird and very unusual for frequent flyer agreements; is it enforced in practice? And where does it say that? I see only "To ensure flight credit, the two letter airline code (AA) must precede the flight number (for example, AA XXXX) on your ticket receipt or boarding pass." (Of course, the whole AS program is unusual in its setup with the large number of partners who don't partner with each other.)