INDIANAPOLIS, June 10 (Reuters) - Low cost carrier American Trans Air Inc. (ATA) said on Monday it has eliminated a fuel surcharge on flights inside the continental United States and cut listed walk-up fares used most often for business travel. ATA, a unit of No. 10 U.S. carrier ATA Holdings Inc. (AMTR), warned on Friday that it expected to report an operating loss in the second quarter and for the year because competition for passengers had forced fares too low. So-called temporary fuel surcharges have been in place for more than two years now and removing the charges will lower fares and is more significant than the fare restructuring, said Tom Parsons, Bestfares.com chief executive. ATA said a simpler fare structure cut listed airfares by 25 percent to 40 percent. Carriers have been forced since the Sept. 11 attacks to offer fares below those list prices because of weak demand for air travel. The fare restructuring is the second aimed at walk-up fares after America West Airlines in March, Parsons said. Walk-up fares can be much cheaper in general on ATA, America West, the No. 8 U.S. carrier and a unit of America West Holdings Corp. (AWA), or Southwest Airlines (LUV) than on the larger major hub carriers, he said. ©2002 Reuters Limited.