Delta Air Lines and American Airlines raised fares by USD$6 to USD$10 on domestic round trips Friday, completing the sixth industry-wide increase of 2009, an airfare expert said.

The moves reflect new pricing power by US airlines as they claw their way out of an economic downturn that eroded travel demand and forced them to cut capacity.

Major US airlines initiated another broad-based domestic fare increase last week.

The most recent fare increases began Thursday with one launched by AirTran Airways, said Rick Seaney, CEO of Farecompare.

"I've never seen one matched this quickly that failed," Seaney said.

Major carriers followed AirTran's lead on Thursday, and Delta and American "filled in the gaps" Friday morning, Seaney said.