Aircraft of the Berlin - Königsberg - Moscow airline at the historic Devau airport in Königsberg, East Prussia, now Kaliningrad in the Russian exclave of that name. Deruluft was 50% owned by the Soviet government and 50% by Lufthansa, and this plane became D-1451 of Lufthansa in July 1928, but went back to Deruluft later. D-1079, the other Do B Merkur on the left, was operated by Deruluft from May 1927 until June 1928 under this German registration. Photo from: Lufthansa

'Landing in Köningsberg - Devau, coming from Moscow, Smolensk and Kowno [Kaunas]'. This was the first scheduled route flown by German-Soviet airline Deruluft from May 1922. Its Fokker F.IIIs had mostly been completed at the Fokker plant in Veere, Netherlands. Photo from: ETH-Bibliothek Zürich

A biplane Fokker airliner? Yes and no - the substantial lower wing of the F.V (F.5) could be removed and it could be operated as a monoplane, although as such it looked dangerously incomplete. Only this example was built and it was tested for two weeks by the German-Russian airline Deruluft, carrying the Russian registration RR13. It became H-NABW in March 1924, and shortly thereafter it was exported to Austria. Photo from: ETH-Bibliothek Zürich