Database: airline
Question: Which airport did Republic Airline fly the most from?
SQL: SELECT T2.DEST FROM `Air Carriers` AS T1 INNER JOIN Airlines AS T2 ON T1.Code = T2.OP_CARRIER_AIRLINE_ID WHERE T1.Description = 'Republic Airline: YX' GROUP BY T2.DEST ORDER BY COUNT(T2.DEST) DESC LIMIT 1