CREATE TABLE aircraft (aircraft_id NUMBER, order_year NUMBER, manufacturer CLOB, model CLOB, fleet_series CLOB, powertrain CLOB, fuel_propulsion CLOB)
CREATE TABLE pilot (pilot_id NUMBER, pilot_name CLOB, rank NUMBER, age NUMBER, nationality CLOB, position CLOB, join_year NUMBER, team CLOB)
CREATE TABLE pilot_record (record_id NUMBER, pilot_id NUMBER, aircraft_id NUMBER, date CLOB)

Show the most common nationality of pilots.
SELECT nationality FROM pilot GROUP BY nationality ORDER BY COUNT(*) DESC LIMIT 1
SELECT "nationality" FROM "pilot" GROUP BY "nationality" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY