US Airways Group Inc. led the Bloomberg U.S. Airlines Index to a sixth straight gain today, the longest in more than two years, on optimism that capacity cuts and fare sales will fill planes and preserve projected profits.

The index, which includes 13 carriers, rose 4.8 percent today and is up 32 percent since March 5. The consecutive daily increases were the most since July 2006.

Delta Air Lines Inc., the world's largest carrier, said earlier this week it plans to cut international flying by an additional 10 percent later this year to trim costs. The biggest U.S. airlines have parked more than 500 jets and eliminated 29,000 jobs to shrink operations since the start of 2008.

"Airline stocks had been under incredible pressure, almost like people were expecting bankruptcies again," said Helane Becker, an analyst at Jesup & Lamont Inc. in New York. "They've taken a lot of capacity out, and they're taking more out, and the idea that they can hold sales and people will book trips is significantly positive," Becker said.