Anyone for a flying submarine?

I stumbled across this old article on the Modern Mechanix website. It from September 1930, but I guess thats really no excuse.

Denmark’s Amazing Submarine Plane

The Danish Navy recently secretly tested a successful plane which not only flies, but which can fold its wings and travel undersea a perfect submarine!

The full article is here: http://tiny.cc/SnE5F

The article states, that the Danish navy has been testing nothing less than a flying submarine (in 1930 mind you). I’m Danish and have never heard about anything even remotely like this (in Denmark anyway), so I was wondering, if any forumites know anything about this. I assume the original writer misunderstood something, but I’m left wondering about what craft could have been the origin of this story. I can see its a Dornier, so Im looking for any other information, that can help me make some sense of the article.