Alaska Air Group ( ALK), the parent of Alaska Airlines and Horizon Air, said its second quarter profit rose more than twofold, due to higher revenue and cost improvements. The company earned $55.5 million, or $1.38 a share, in the quarter, compared with $17.4 million, or 56 cents a share, a year ago. Adjusted for items, the company earned $60.3 million or $1.50 a share in the most recent quarter. Analysts polled by Thomson First Call were expecting earnings of $1.29 a share. Second-quarter revenue rose 15.4% to $873 million as against analysts' expectation of $854.5 million. Revenues for the quarter were mainly driven by revenue from passenger business which grew 15.8% to $807.4 million. Alaska Airlines' passenger traffic increased 7.2% on a capacity increase of 5.2%. Operating revenue per available seat mile increased 9.5% while its operating cost per ASM excluding fuel, restructuring charges and adjustments decreased 2.1%. Alaska's load factor increased 1.4 percentage points to 79.3%, compared with the previous year quarter. Horizon Air's passenger traffic increased 11.3% on a 6.1% capacity increase and operating revenue per ASM increased 9% while its operating cost per ASM excluding fuel increased 9.8%. Horizon Air's load factor increased 3.6 percentage points to 76.6%, compared with the previous year quarter. Aircraft fuel expenses, including hedging gains and losses, increased to $199.8 million in the quarter, compared with $147.7 million in the year-earlier period. "We are extremely pleased with this quarter's earnings, which were the result of a combination of revenue gains and cost improvements," said Bill Ayer, chairman and chief executive officer. "It's gratifying to see everyone's hard work pay off, and I would like to thank and congratulate our employees on an outstanding quarter." Shares rose $1.46 Tuesday to $37.36.