Labor Day expected to carry summer travel to all-time high

Labor Day air travel in the United States will be even busier this year than last.

U.S. airlines are expected to carry 14.2 million passengers worldwide from Wednesday, Sept. 2, through Tuesday, Sept. 8, up 3 percent from a year earlier, Washington-based trade group Airlines for America said on Tuesday.

The group has forecast that summer travel will reach an all-time high on the wings of a strong U.S. economy. Passenger traffic grew 3 percent in the first half of 2015, although a 3-percent decline in fares during the same period kept operating revenues flat for U.S. carriers, Airlines for America said.

Yet a 34-percent decline in fuel costs, airlines' greatest variable expense, has boosted their profit.

"Six years post-recession, airlines are finally realizing profit margins that are on par with the S&P 500 average, a barometer of U.S. corporate performance," the group's Chief Economist John Heimlich said.

The 10 publicly traded U.S. airlines collectively had a profit margin of 11.2 percent in the first half of 2015, up from 4.9 percent in the prior year, according to the group.