Southwest Airlines Co and JetBlue Airways Corp both wanted American Airlines and US Airways Group Inc to give up as many flight slots as possible at the Reagan National Airport in Washington. The carriers openly pronounced their interest in acquiring slots at Reagan National following a lawsuit filed in early August to block the merger of the latter. American Airlines and US Airways Group Inc, currently the third and fifth largest US airline, announced plans of an impending merger in February of this year.

According to Southwest and JetBlue, a merger of the giant carriers would generate AMR-US Airways' control over an unacceptably high percentage of flights in Reagan National. AMR Corporation is the parent company of American Airlines.

Southwest said the increased concentration of flight slots brought about by the AMR-US Airways merger would substantially lessen competition. "Those anticompetitive effects could be mitigated only if a significant number of slots were divested to Southwest," the carrier said.

Although declining to comment on the issue, sources said both Southwest and JetBlue were currently in discussions with the US Department of Justice about acquiring flight slots in Reagan National and LaGuardia Airport in New York.