CREATE TABLE AIRPORTS (City VARCHAR(255), AirportCode VARCHAR(255)); CREATE TABLE FLIGHTS (SourceAirport VARCHAR(255))
Which city has most number of departing flights?
    
SQL: SELECT T1.City FROM AIRPORTS AS T1 JOIN FLIGHTS AS T2 ON T1.AirportCode = T2.SourceAirport GROUP BY T1.City ORDER BY COUNT(*) DESC LIMIT 1