Give the air carrier description of the flights that have an earlier arrival and departure.
earlier arrival and departure refers to ARR_DELAY < 0 AND DEP_DELAY < 0;
SELECT T1.Description FROM `Air Carriers` AS T1 INNER JOIN Airlines AS T2 ON T1.Code = T2.OP_CARRIER_AIRLINE_ID WHERE T2.ARR_DELAY < 0 AND T2.DEP_DELAY < 0 GROUP BY T1.Description