The following relations keep track of the airline flight information:
Flights (flno: integer, from: string, to: string, distance: integer, departs: time, arrives: time, price: real), Aircraft(aid: integer, aflame: string, cruisingrange: integer), Certifled( eid: integer, aid: integer), Employees( eid: integer, ename: string, salary: integer).
Note that the Employees relation describes pilots and other kinds of the employees as well; every pilot is certified for some aircraft, and only pilots are certified to fly. Write down each of following queries in SQL.