Southwest Airlines Co said on Friday that its AirTran subsidiary would stop operating at six U.S. airports this year because of higher fuel costs.

Airports that will lose AirTran service as of August 12 are in Allentown and Harrisburg, Pennsylvania; Lexington, Kentucky; Sarasota, Florida; Huntsville, Alabama; and White Plains, New York. Southwest said in a statement that AirTran workers at those airports would have a chance to move within the company once those operations ended.

AirTran operations will continue at 22 U.S. and international airports in such places as Charlotte, North Carolina, Washington, D.C., and Cancun, Mexico, and will eventually be converted to Southwest.

AirTran President Bob Jordan said in the statement the company was discontinuing service in markets it could not make work because of fuel costs.

Southwest acquired AirTran last year, gaining access to big East Coast markets such as Atlanta. The carrier expects to receive a single operating certificate in the first quarter, but until then must operate AirTran as a separate entity.

Shares of Dallas-based Southwest were up 1.3 percent to $9.42 in afternoon trading on Friday.

(Reporting by Karen Jacobs)