This is the famous Fokker Dr1 triplane of Manfred Von Richtoffen. Known as "The Red Baron", that pilot was the most famous ace of WWI, and Snoopy's archenemy.
This is a paper model at 1:50 scale. I spent 29 hours building it, and you can see detailed photos of the process here: Red Baron's Fokker process.
You can see another picture of it, "flying" against the sky, here in my gallery: Fokker Dr1 flying