People of German descent

I've been listening to several David paulides/missing 411 podcasts. He notes notes that a large percentage of the people that go missing are of German descent. He alludes to the belief or mytn of where Germanic people came from having some kind of correlation to them disappearing in the wilderness. I have a basic knowledge of Germanic/celtic/norse/Gaelic mythology and I do not understand the reference. Any pertinent information would be greatly appreciated. Is he referring to some kind of norse gods=aliens theory?