The internet is like an old attic where you discover hidden treasures buried under old blankets. I was surfing the web, looking for something, and stumbled across an amazing archive of scanned performance data for 1940s fighter aircraft. You’ll find copies of flight test reports from many of the fighter aircraft used by Great Britain, the USA, Germany, and Japan during World War II. This includes the very earliest jets. We find such gems as:

In short, it is a gold mine for anyone interested in World War II fighter aircraft.