CREATE TABLE AIRLINES (Airline VARCHAR(255), uid VARCHAR(255)); CREATE TABLE FLIGHTS (Airline VARCHAR(255), SourceAirport VARCHAR(255))
What are airlines that have some flight departing from airport 'AHD'?
    
SQL: SELECT T1.Airline FROM AIRLINES AS T1 JOIN FLIGHTS AS T2 ON T1.uid = T2.Airline WHERE T2.SourceAirport = "AHD"