At JetBlue, TrueBlue members get $15 off round-trip flights when paying by American Express. (TrueBlue membership is free.) That's one of the few discounts we've seen from JetBlue this year. The flight must be booked by December 17.

Note: Sign up for The JetBlue Card from American Express and get 50 TrueBlue points for free. (100 TrueBlue points equal a round-trip ticket to anywhere.)