AirTran Airways, on the verge of merging with Southwest, was the big winner in this year's Air Quality Index study of carrier performance based on U.S. Department of Transportation statistics for on-time flights, bag handing, complaints and bumped passengers. Here is a good AP roundup of which airlines performed best in various categories.
Not mentioned in the AP story is how PHL's big carrier, US Airways did. As COO Robert Isom pointed out today to employees in a message, US has steadily gotten better in this particular ranking, and based on 2010 numers ranked 6th overall, up from 8th last year. The result put US ahead of all other older hub-and-spoke airlines that it considers its primary competitors.