The U.S. Bureau of Transportation Statistics said airlines sold 2.9 percent more seats on planes in May than they did in May of 2009 -- using figures released in mid-August.
The Los Angeles Times reported Monday passenger capacity also rose, up to 82 percent of seats available, compared to 80 percent a year ago.
When the economic downturn hit, many airlines began grasping at straws, adding fees for checking baggage and providing blankets, and for privileges like early boarding.
Despite indications U.S. consumers are willing to travel again, however, "most of the fees we see are here to stay," said George Hobica, founder of Airfarewatchdog.com.
A second industry expert, Rick Seaney, co-founder of Farecompare.com, said some fees may go down, but "I don't think we will ever not see bag fees."
Airlines continued to add fees this summer with American Airlines adding an "Express Seats" option which costs $19 for short trips and $39 for long trips and allows passengers in coach to be "among the first" to board in that section to choose a seat, the airline's Web site says.
AirTran Airways said it would charge $20 to check the first bag, up from a previous price of $15.
AirTran also raised the fees for unaccompanied minors from $39 to $49 for non-stop flights and from $59 to $69 for trips that require changing planes, the newspaper said.
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