Anniversary cover with colorful cachet showing the LZ7 Zeppelin in flight. Cover is signed at the top by T.A. Knowles who had a colorful career in airships: he was an engineer at Goodyear-Zeppelin, first flew in a blimp in 1927 and was on the Akron, Macon, Graf Zeppelin and Hindenburg. During WWII he made blimp flights for the U.S. Navy. 6.5x3.75", cover condition is mint.