Provide the air carrier description of the flight with a tail number N922US from Phoenix.
tail number refers to TAIL_NUM; TAIL_NUM = 'N922US'; from Phoenix refers to ORIGIN = 'PHX';
SELECT T2.Description FROM Airlines AS T1 INNER JOIN `Air Carriers` AS T2 ON T2.Code = T1.OP_CARRIER_AIRLINE_ID WHERE T1.TAIL_NUM = 'N922US' AND T1.ORIGIN = 'PHX' GROUP BY T2.Description