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

What are the names of the aircraft that the least people are certified to fly?
SELECT T2.name FROM certificate AS T1 JOIN aircraft AS T2 ON T2.aid = T1.aid GROUP BY T1.aid ORDER BY COUNT(*) DESC LIMIT 1
SELECT "T2"."name" FROM "certificate" "T1" JOIN "aircraft" "T2" ON "T1"."aid" = "T2"."aid" GROUP BY "T1"."aid" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY