I just assumed someone in the states green lighted the distribution. Interesting that it was made by Europeans.
Nope. US distribution (such as it was) was handled by a Canadian company, Entertainment One.
What's interesting about Iron Sky is that the filmmakers made a trailer, basically as a home movie, doing all the effects themselves. Then they sent the trailer around to festivals and things like comic book conventions, building an internet buzz that they were able to leverage into raising the money to finish the film.