OFFENBACH 12.6.12, airmail stamp 10 Pfg together with 5 Pfg Germania on gray brown airmail postcard, ribbed box, written aboard the Swabia, reverse". . . From my trip with the airship Swabia. . . Frankfurt a / M i. D. Aerial 10 VI 1912", to Frankfurt / M. Bonames, vertical trace of crease outside of the franking