The first jet to fly was the Heinkel He 178, in 1939. But the first operational ... As military pilots were transitioning from piston- to jet-powered aircraft, the U.S. was transitioning, too ...

When the Heinkel He 178, the first pure turbojet aircraft, first flew in 1939, it did so with 4.41 kilonewtons (kN) of thrust; the number 1 entry in our list has a quite bonkers 1776kN.