cover Germany, Bavaria, 1913, 25pf Dark Prussian Blue Air Post semi-official (Michel F1), unused, o.g. single and another tied on 1913 flight card to Switzerland with additional 10pf Scarlet on buff (79), reverse with multi-colored illustration of early plane, faint staining in one corner of card (from a corner mount), otherwise fine-very fine, Michel DM 1,700.00