In science fiction, conspiracy theory, and underground comic books, stories or claims circulate linking UFOs to Nazi Germany. These Nazi UFO theories describe supposedly successful attempts to develop advanced aircraft or spacecraft prior to and during World War II, and further claim the post-war survival of these craft in secret underground bases in Antarctica, South America or the United States, along with their creators.Within the canon of media various code-names or sub-classification of UFO craft are identified: Rundflugzeug, Feuerball, Diskus, Haunebu, Hauneburg-Geräte, V7, VRIL, Kugelblitz, Andromeda-Geräte, Flugkreisel, Kugelwaffen, Reichsflugscheiben.
Accounts appear from as early as 1950, likely inspired by historical German development of specialized engines such as Viktor Schauberger‘s “Repulsine” around the time of WWII. Elements of the claims have been widely incorporated into various works of fictional and purportedly non-fictional media including video games and documentaries, often mixed with more substantiated information.