A dispute over Southwest Airlines Co.’s requirement that certain employees use their fingerprints to sign into and out of work does not belong in court, a federal judge held.In a written opinion last week, U.S. District Judge Marvin E. Aspen threw out a proposed class-action lawsuit accusing Southwest of violating the Illinois Biometric Information Privacy Act.Aspen held the suit is pre-empted by the Railway Labor Act, which governs collective bargaining agreements in the railroad and airline industries.The act …