busiest source airport
select t1.name from airports as t1 join routes as t2 on t1.apid = t2.src_apid where t1.country = 'China' group by t1.name order by count ( * ) desc limit 1
what is the source airport id?
select t1.apid from airports as t1 join routes as t2 on t1.apid = t2.src_apid where t1.country = 'China' group by t1.name order by count ( * ) desc limit 1
what is the airline for source airport?
select distinct airline from routes where src_apid = ( select t1.apid from airports as t1 join routes as t2 on t1.apid = t2.src_apid where t1.country = 'China' group by t1.name order by count ( * ) desc limit 1 )