Flying Tiger

The color on your scan looks more army field gray than air force gray blue--but then it scans as the same looking as his Luftwaffe pilot badge, so must have been worn with that.

This might bear more research: I have seen both badges in-hand and there is a marked difference in the gray background. That of the Naval Zep badge is much lighter. Could it have been worn on a Weimar tunic of some sort? Construction certainly looks like many of the early 1930's pieces I have seen: just have not seen much in bullion with strict provenance to circa 1920. In any event, a stunning piece. As for the Luft badge: possibly a Pilot-Observer with the 2 colors to the bullion or just a difference in material? At the MAX I saw 3 or 4 bullion (Real: from reputable Sellers) Pilot badges and the eagle and wreaths were all made of the same type/color bullion...

Wearing the NEVER Encountered (at least on the eastern side of the Atlantic!) LZ-insigned cap! Remarkable!