This paper model is a Nazi Flying Saucer (Nazi UFOs), named Haunebu. The disc aircraft is alleged out of this world technology that was possessed by the Nazi in 1940s during World War II. The paper craft is created by Julius Perdana. This myth also adapted into a movie "Iron Sky".
In science fiction, conspiracy theory, and underground comic books, stories or claims circulate linking UFOs to Nazi Germany. These German 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.
You can download the paper model here: Haunebu II & III Nazi Flying Saucer (Nazi UFOs) Free Paper Model Download