When were jet engines invented?

In the 1940s the Nazi German aviation engineers developed the first working Jet engines and planes. There were a few that flew in combat. Many of the jets they produced sat and were never used because the war ended. The US, Brits and Russians grabbed the technology and the planes. They also were able to get the engineers too. However, the jet engine was patented by a British engineer long before the Germans developed the jet engine. See related question below.

Edit; Sir Frank Whittle was the first to realise that the power of an engine was primarily based on how much oxygen it could ingest. This led him to invent the jet engine and the Germans, having read of his design pre-war, lost no time turning it to their advantage.