Air Tran has probably the best customer service around. They will work with you. If those times don't work for you they will gladly refund your entire fare, move you to another flight that does work for you, move you to a flight on a different day, or even allow you to fly with them out of another airport, without charging you a thing.
This past Oct 9th-17th my husband and I was going down to WDW. We didn't realize that first weekend fell on my husband's weekend to be on call. My husband's boss decided to be a horse's tail and refused to let him switch weekends with a coworker, who had agreed to cover for him. We decided that I'd go ahead and fly down on Saturday and my husband would fly out on the first flight on Monday morning. A few weeks after we bought our airline tickets my husband's boss, came back to laugh and say he'd just been joking.


Knowing how flexible Air Tran is and that if they change you flight by even a few minutes you can either cancel or even move your flight to another day, I waited hoping that Air Tran would change one of his flights. They moved my departing flight up by 30 minutes, but didn't touch his. His return flight they finally changed by like 2 minutes. I waited until just a few weeks prior to the trip before I finally gave up. I called, expecting to pay out the nose. I expected to pay the change fee, plus the difference in fare. I got a very nice customer rep and when I explained the situation and asked how much it would cost to get him on my flight, I laughed and said if it was too much, he'd just have to fly out by himself on Monday. The rep laughed and said no we needed to be together, so let him see what he could do. After putting me on hold he came back and told my my husband's return flight had changed by a couple of minutes, but not his departing flight, which didn't help us. I told him I knew that and just wanted to know what it would cost to get him off the Monday flight and onto my Saturday flight. He said he was going to see what he could do for me and again put me on hold. After several minutes he came back laughing and said he'd performed some magic and had not only moved my husband to my flight, but had put him in the window seat, next to my aisle seat, and it was done as a courtesy move, so wouldn't cost me anything.

(We had prepaid for each of our seats when we booked our respective flights).
Last Dec they changed my nonstop flight to one with a long layover in Atlanta. I called and while there was no longer any direct flights, they offered to either refund my complete fare, switch to a direct nonstop flight the day before or the day after, or move me to a different flight. I took the earlier flight with a shorter layover, but it was my choice. I could have flown out the day before on a nonstop flight.
Anyway, give them a call. You probably won't have any trouble having them just move you to a flight out of the other airport. It won't even matter if that flight is more expensive. I know my flight had gone up significantly since we'd booked our flights, but we didn't get charged the difference and I've read several posts on here where people have had to change flights, even days or airports and didn't get charged the price difference. If Air Tran makes a time change of even a few minutes they will bend over backwards to accommodate you.