A federal judge tossed a lawsuit against United Airlines Tuesday, ruling that the airline did not discriminate against an elderly flight attendant when it fired her.Gale Clapper, who was 66 when she was fired in May 2019, sued United Airlines for discrimination in 2020 on the basis of age and disability and accused the airline of interfering with her benefits. She alleged that United violated the Americans with Disabilities Act (ADA), Age Discrimination in Employment Act and Employee Retirement Income Security Act.In a …