I have been reading The Hunt for Zero Point by Nick Cook and I am more convinced than ever that The Skunk Works have used technology from the Nazi secret project Die Glocke (The Bell) during WWII to power the new project Aurora spy plane.
Read more about my views on German technology in an interview I did on the Alternative History Fiction website.
The extraordinary Die Glocke is reputed to have used anti-gravity technology, though it is likely to have caused many deaths, directly, and indirectly when the SS murdered all the scientists working on the project.
If you want to read more about secret technology, pick up a copy of my new book December Radio. Or read about Die Glocke (the Nazi Bell) which used the prototype technology for Project Aurora, in my subscription novel Rip.