AirTran tops annual airline ranking

Dallas-based Southwest expects to close its buyout of AirTran in the next few months. AirTran has its largest hub in Atlanta, and the deal will bring Southwest to Atlanta.

Southwest, for its part, ranked 5th, on par with its performance in the previous year.

Atlanta-based Delta Air Lines ranked 7th, up significantly from its No. 15 ranking in the previous year. Delta had the highest rate of customer complaints last year.

"We have seen based on our performance that we were facing challenges in 2010 and we took a number of steps to improve that performance," said Delta spokesman Anthony Black. Among the issues is the complexity of Delta's operation, with seven hubs across the country and a network of international flights around the world.

The Airline Quality Rating study, conducted by professors at Wichita State University and Purdue University, also showed that overall airline performance improved last year to the third best overall score in the last 20 years.

Purdue University professor Brent Bowen, a co-author of the study, noted that

past AQR date suggests that combining two large airlines often results in lower rankings.

"We will be carefully watching to see if two highly rated carriers, such as No. 1 AirTran and No. 5 Southwest, will reverse this trend," he said in a written statement.

AirTran spokesman Christopher White said Southwest's takeover of the Atlanta hub "will have its own challenges" but he added that there are many areas in the country without overlap between the two carriers, which could reduce the need for consolidation.

White said Southwest management has taken steps to learn about AirTran's best practices, such as its baggage handling performance. AirTran was the best performer in baggage handling, while Southwest was the best performer in keeping customer complaints down.