i am getting the impression that you may think Air Tran is a charter co.
Air Tran is one of the "discount" airlines, similar to Spirit. It is now owned by SWA and will be flying under the name SWA in a year or so. I may be wrong, but years ago i think it was called Valu Jet. Maybe Chadd can correct me on that?
Valujet purchased airtran and renamed the entire company AirTran in an effort to avoid the stigma after the crash in the everglades.