Technically, any gas-powered turbine that makes thrust by expelling hot gases at high speeds qualifies as a jet engine. However, turbojet and turbofan engines generate forward motion.

Jet-powered trains once promised a sleek, high-speed future for American rail. With roaring engines and record-breaking speeds, the concept was bold but ultimately unsustainable. This video uncovers ...

A Stanford.edu article details that Whittle patented a turbojet design as early as 1930, but his first jet-powered aircraft didn't fly until 1941. Ohain, meanwhile, got there first.

Technically, any gas-powered turbine that makes thrust by expelling hot gases at high speeds qualifies as a jet engine. However, turbojet and turbofan engines generate forward motion.