Originally Posted by
cubeman
AF has always offered me $500-$550 each way on Day of departure upgrades if space is available. Delta has only quoted me the current face-value to buy the ticket at check-in.
Used to be an attractive ~$500 but I think nowadays it's closer to $750
DL has offered this when you check in on the app at some point but I haven't seen it in years. Wasn't that cheap, ~$750 range as well