Originally Posted by
eponymous_coward
AF/KL issue cards through Bank of America like AS does, and they also partner with EVERYONE in the transferrable miles space: AMEX, Chase, Capital One, Citi, Bilt, Wells Fargo. So maybe BofA won't care. Maybe AS won't care if they lose some control of their mileage minting (I suspect they view BofA not having transferrable miles as a feature, not a bug, it helps with controlling the program).
US credit card issuers pay more for miles from US-based airlines than those from foreign airlines, so they probably care more about exclusivity with these US-based airlines. Foreign airlines (including BA, VS, AF, etc.), I guess, are "permitted" to have more "promiscuous" relationships.