Originally Posted by COpltASgldPHX

It will only show up that way on AS.com. All QX flights are AS codeshares and show up that way in all of the GDSs. There is no way to actually book a QX flight using the actual QX flight number. The actual QX flight number is the last three digits of the AS flight number. For example AS2244 is actually QX244 even though it displays on the website as QX2244. The three digit flight number is what is used with flight tracking and when the crews call ATC etc.

As for the whole interline baggage/ticketing thing it is not tied to IATA. Although most IATA member airlines do have interline agreements with each other all interline agreements are negotiated by each individual airline. Also it isn't necessary to have an interline ticketing agreement to have an interline baggage agreement.