What is the name of the airport in Mount Hagen city?
select name from airports where city = 'Mount Hagen'
Return the number of routes with destination airport in Italy operated by the airline with name 'American Airlines"?
select count ( * ) from routes as t1 join airports as t2 on t1.dst_apid = t2.apid join airlines as t3 on t1.alid = t3.alid where t2.country = 'Italy' and t3.name = 'American Airlines'
How many active airlines are on the list?
select count ( * ) from airlines where active = 'Y'
What is the elevation of Madang Airport airport?
select elevation from airports where name = 'Madang Airport'