Searching for 2 people in both cases. The DL fare books into C, but I'm unable to ascertain what the IAP fare is booking into, using amextravel.com. Assuming it is Z, does that mean IAP can access fare classes that DL can't? That wouldn't make much sense, unless they were put aside specifically for Amex.
Originally Posted by
MSPeconomist
Start by looking carefully at the fare code and fare rules. My guess is that the $3900 is a Z fare and $10,300 probably C (maybe D, but probably too cheap to be FULL J). Also, are you searching for *two* people in both cases, as there could be one ticket remaining at $3900 with the second passenger on the same PNR pushing the price up to $10,300 for each person.
Are you calling AmEx or using their website? I would assume/hope that they use real time inventory for DL, but that could also be an explanation. Maybe the cheaper fare won't actually ticket.
IME IAP offers discounts on fares that are normally available from DL (same fare code, just a designator), but I've seen Z fares that AmEx doesn't see and can't ticket under the IAP.