SELECT count(*) FROM airport WHERE id NOT IN ( SELECT airport_id FROM flight WHERE pilot  =  'Thompson' );
How many airports haven't the pilot 'Thompson' driven an aircraft?
SELECT count ( * ) FROM airport WHERE id NOT IN ( SELECT airport_id FROM flight WHERE pilot = 'Thompson ' ) ;
select count ( * ) from airport where id not in ( select airport_id from flight where pilot = value )
How many airports have n't the pilot 'Thompson ' driven an aircraft ?