I never called AirTran, but I did call WDTC, whom I booked the flights through. The CM put me on hold to ask "air help" (the people who do the air reservations, but whom customers never talk to), and the message returned to me was that AirTran not only won't refund or credit the difference, but they also won't allow you to pay the $50 change fee to rebook on the same flights. They WILL allow you to change to a DIFFERENT flight, however, but if you're like me, you chose specific flights for a reason, so that option didn't appeal to me. I never checked directly with AirTran, and we've all known Disney CMs to provide less than accurate info in the past, but I'm not optimistic.