Dao sought to preserve surveillance videos and cockpit recordings of the incident after he lost two teeth and suffered a concussion and broken nose.
Dao refused to deplane after being randomly chosen by the airline to make room for additional crew because he had patients to see. He returned to the plane after the incident but does not remember doing so due to his concussion.
United Airlines officials said in a statement it will no longer allow officers to remove booked and seated passengers and will review how it “incentivizes” oversold planes.