CREATE TABLE employee (eid NUMBER, name CLOB, salary NUMBER)
CREATE TABLE aircraft (aid NUMBER, name CLOB, distance NUMBER)
CREATE TABLE flight (flno NUMBER, origin CLOB, destination CLOB, distance NUMBER, departure_date TIME, arrival_date TIME, price NUMBER, aid NUMBER)
CREATE TABLE certificate (eid NUMBER, aid NUMBER)

How many aircrafts exist in the database?
SELECT COUNT(*) FROM aircraft
SELECT COUNT(*) FROM "aircraft"