Originally Posted by findark

I did not read the whole thing in depth, but I'm not quite sure how the information reflects on the profitability of the Amex relationship. I read the first link, and it shows $3.46b of direct passenger revenue (tickets), $1.1b of "mostly lounge access" (honestly startling if true), $1.7b of probably mostly baggage fees, and a more opaque $3b in "loyalty program revenue".

But at the end of the day, there are allocable costs to Delta to providing all or most of these services, like actually operating the flights that Amex purchases travel on, operating the lounges that Amex buys into, and so-on. And honestly, characterizing revenue which is backed by the costs of operating flights as "ancillary" seems flat-out wrong to me.

My point is that I'm sure Delta is doing well by this relationship, and it's obviously big, but there's no easy way to judge exactly how profitable it is, or that the profit of selling more premium cabin seats directly to passengers instead of using them to incentivize Amex card spend is or isn't a net win for Delta. To use myself as an example, I'm a huge spender into the Delta Amex ecosystem... but that's because it pays back huge benefits compared to UA, where I never got into the Chase/UA cards. Am I actually profitable to the Amex relationship? I highly doubt it.