Graf Zeppelin Balkan Flight cover
The LZ127 Graf Zeppelin's Balkan Flight included official drop mail at Bucharest in addition to other drops over such cities as Vienna, Belgrade, Sofia, and Kronstadt. This Bucharest drop cover has the on board postmark and the new red zeppelin flight cachet. 1 RM was the new zeppelin letter rate. In addition the cover has a red private zeppelin on-board cachet and the red Bucharest airmail postmark.