Originally Posted by
bgriff
I think the OP is referring to a club lounge membership ($$$) hence needing to choose. I agree they should certainly be both an AAdvantage and MileagePlus member, and would hope they already are. (And depending on the nature of their flying, may stand to get better overall benefits and experience by trying to consolidate flying into one program or the other.)
Oops, I interpreted club as FF program.