Responders on Saturday boarded the plane in Phoenix and removed a man who was asked to put on a medical mask.
US Airways spokesman Bill McGlahsen says the airline was notified after the plane departed Austin that the passenger's status had been changed to "no-fly" because of an unspecified medical condition.
Federal and Maricopa County health officials said there was no immediate confirmation that the passenger has an infectious disease.
Tuberculosis is a respiratory disease that can be fatal. The Centers for Disease Control says it is spread through the air.