If your flights change or if the price drops, I believe it is much easier to just be able to call Airtran directly to request different flights or a refund of the price reduction in your ticket. I always booke Airtran directly with Airtran.
Airtran is new to our market and they are having promo fares of $59 each way. They have added sale fares for $69 so I really don't think they will drop lower but will go higher. Allegiant did the same with $44 fares and now they have surged to $79 each way. Afraid Airtran will follow very soon. Airtran is pushing they can fly one way for $100 so I expect the fare to go up..