I'm not sure if it's such a bad idea in this case though. I don't know how much the marginal cost of a seat on a flight to London is, but it's a hell of a lot less than retail. Provided this handful of AAirpass customers aren't, in-and-of themselves, generating more flights that AA has to schedule, their actual sticker price to the company cannot be accounted for at retail prices.
But if the AAirpass people displace other passengers who would have paid retail and instead went to another airline, this opportunity cost should be assessed at retail.
