Motorenfabrik Oberursel, Fokker E-III Monoplane. By the great German poster artist Ludwig Hohlwein, who unfortunately later on created propaganda posters for the Nazis. Shockingly, the wikipedia entry on Hohlwein makes no mention of it.
Ludwig Hohlwein - c Oberurseler Umlaufmotor/ Motorenfabrik Oberursel (company that manufactured rotary engines for automobiles, locomotives and aircraft. During the first World War they were primarily designing aircraft engines)