Stupidity: The plans Hochstetter and Burkhalter find in Hilda's desk turn out to be for the Hindenburg, a large dirigible. Burkhalter says he never saw the plane (sic) they show before. The Hindenburg was a German propaganda icon and very well known to every child in Germany. It's nigh impossible a Luftwaffe (Air Force) general would not recognize plans of a dirigible when he saw them, or not know the Hindenburg. Note that despite everything, the plans from Hilda's desk are probably meant to be not the same ones Carter later says he found inside the boxes - A Luftwaffe general not recognizing the difference between a jet plane and a dirigible is even more stupid. To avoid unnecessary corrections: Yes, according to the boxes the kits aren't for the Hindenburg but for JU-87 Stuka bombers, but that's a different mistake and not relevant for this one.