Yeah those ones are probably BS. But there are some theories about their science/secret-science that actually have some weight in them. The Nazis did built machines that looked like UFO's for instance. Look it up.
There are so many Nazi conspiracy theories/myths around its hard to keep up with them Recently read one about the SS trying to breed werewolves to invade switzerland
My grandfather fought in WW II and during my work in hospitals/old folks' homes I met a lot of other former soldiers, never heard anything about UFOs or something similar.