Fairfax County supervisors decided yesterday to end their fight to stop the supersonic jetliner from flying to Dulles International Airport.

The supervisors' action came after the Court of Appeals in Washington refused to review a suit brought by the county challenging the Federal Aviation Administration's exemption of the Concorde from noise levels set for other supersonic aircraft.

The county had contended that an environmental impact statement developed by the FAA failed to assess fully the impact of Concorde noise levels on areas near the airport.

Noting that the appeals court had handed down a one-sentence rejections of the county's suit, Fairfax Board Chairman John F. Herrity said it "would be a waste of taxpayers' money" to appeal the decision to the Supreme Court. The appeals court acted late last month.

The supervisors voted 6 to 2 to end the suit, with supervisors Martha V. Pennino (D-Centreville) and Marie B. Travesky (R-Springfield) casting no votes. Supervisor Sandra L. Duckworth (D-Mount Vernon) was absent at the time of the vote.

The FAA's decision to exempt the Concorde's flight from existing noise level standards followed a determination that Concorde noise levels were as low as possible for the airport. Concorde jets currently fly into New York, Dallas and Washington.