The newest airline to serve Bermuda, AirTran, has been officially bought by Southwest Airlines.The purchase makes the combined low cost carrier one of the largest US airlines.The Associated Press reported that very little will change for the airlines for the time being.“There will be separate websites, frequent-flyer programmes and bag-fee policies. AirTran charges for checked baggage, while Southwest allows two bags for free,” the AP said yesterday.AirTran began flying to Bermuda from Baltimore in April and will begin flying from Atlanta on May 26.Bob Jordan, the Southwest executive who will run AirTran, said Southwest probably won’t do away with bag fees or AirTran’s first-class cabins or even repaint the planes in Southwest colours until at least next year. Southwest expects to get a single operating certificate from the Federal Aviation Administration in the first quarter of 2012.By buying AirTran Holdings Inc., Southwest gains its first presence in Atlanta and at Reagan National Airport in Washington, plus additional gates at New York’s LaGuardia Airport.