Each is 13/16" with airplane or pilot against color background. Set was produced by Greenduck Co. Chicago in the 1930s and each button is numbered. The first two buttons are captioned "Early Plane 'Pusher' Type" and "Dr. Rumpler's Taube German 1911." Other famous planes and pilots include: "Van Richthofen's Fighter, Ford Tri-motor, Douglas DC-2, Navy "Hell Diver", Wiley Post's "Winnie Mae", Famed Wright Bros' 'Pusher' Plane" as well as portraits of Orville Wright, Glenn Curtiss, Eddie Rickenbacker, Charles Lindbergh, Capt. Frank Hawks, Jimmy Mattern, Roscoe Turner, Howard Hughes, and the set concludes with five female pilots including Amelia Earhart Putnam. The two missing are #20 and #45. These show white craze lines: 3,16,17,18,19,29,41,42,63,65,67,68,. These have small scratch, scuff or dents: 1,4,11,27,39,52,62,64. Of the 68 here, 48 are Exc. to Mint. Our Hake Collection NM set in Auction #206 exceeded $600.00.