Originally Posted by
broog
So amex does pay the airline something. Ok, but who ends up paying after that? Its an expensive seat that could have otherwise been sold for $$$. Would it be the airline that the reservation was made through, or the partner airline that was actually flown?
If the airline actually thought that they'd sell the seat they wouldn't make it available for points.
As for the cash exchanged between carriers, they have contracts that dictate the rates and that is in part how they determine the number of points to charge for a reward ticket on partners. That's why you'll find some carriers (CO definitely does this) that have different rates depending on the carrier used.