I think a point to keep in mind is that even though BB has mentioned alliance membership, at this point a simple frequent flier partnership would probably be most beneficial. Codesharing would be a welcome addition down the line for the right partner but even the Delta partnership was lopsided. Their frequent fliers would probably be very happy to have access to international destinations to earn/redeem miles, whether or not they are on F9 metal for part of the trip or not.