DOW JONES NEWSWIRES Southwest Airlines Co.'s (LUV) July traffic rose 5.9% as the airline flew more trips than a year earlier. Southwest, the largest domestic U.S. airline by passenger numbers, bought discount carrier AirTran earlier this year for $1.4 billion. Thursday, the company reported its second-quarter earnings jumped 44% as results benefited from the acquisition of AirTran and higher traffic. Combined revenue passenger miles rose to 10.05 billion from 9.49 billion a year earlier. Capacity rose 6.6%, while load factor--the percentage of available seats filled--edged down to 85.1% from 85.6%. During the month, Southwest flew 125,428 trips, a 3.2% increase from last year. Shares closed Thursday at $8.84 and were recently up 3.2% in premarket trade. The stock is down 32% since the start of the year. -By Mia Lamar, Dow Jones Newswires; 212-416-3207; mia.lamar@dowjones.com