Passenger traffic and a key revenue measure are up at Southwest and AirTran.
Dallas-based Southwest Airlines Co. said Thursday that passengers flew 7.41 billion miles last month, up 2.2 percent from January 2013. Most of the increase was due to longer trips -- the average rose to 961 miles. The number of paying passengers rose just 0.3 percent.
Revenue from every seat flown one mile rose about 5 percent from a year earlier.
Southwest says part of increase was due to flights that were canceled during winter storms, as some displaced passengers were put on other flights, making them more crowded.
The figures include both Southwest and its AirTran subsidiary, which the company is phasing out by year's end.