A fight broke out onboard an Allegiant Air flight from Phoenix to Provo, Utah after a passenger refused to wear a face mask as required by the airline. The fight started when a passenger who wore a face shield got into an argument with a flight attendant over wearing a face mask. A spokesperson for Allegiant Airlines did not respond to questions regarding the incident, but told NBC News on Monday that the airline requires all passengers to wear face covering at all times, including at the ticket counter, gate area and for the duration of the flight. According to company policy: “Face shields may be worn in addition to a face covering, but not as an alternative.” The video shows another man, clad in a mask that doesn’t cover his nose, throwing jabs at the passenger who refused to wear a mask while being held back by flight staff. The fight was broken up after 30 seconds. The passenger without a face mask was escorted off the plane by flight attendants, while the other man was allowed to stay.