This is one time that a codeshare may actually be useful! AA is prohibited by the US govt from accepting any IATA issued ticket that has any segment for Cuba ... but QF is not, and AA acting as QF's agent is allowed (I think). Thus you cannot have AA flight number MIA-LAX but can have QF flight number MIA-LAX (but note that you can only do this, even on a OWE ticket, if you are flying out of LAX on QF metal as the next segment -- so it isn't much of a loophole!). Pretty sure QF will not sell you any of the US codeshares except as continuation of a trans-pacific QF flight (they probably lose money on MIA-LAX).