The Fokker D.I (company designation M.18) was a development of the D.II fighter. The D.I was also flown in Austro-Hungarian service as a fighter trainer aircraft under the designation B.III. Confusing the matter further, both the D.II and D.I arrived at the Front in German service at similar times, in July–August 1916. The main designer was Martin Kreutzer. Control was achieved using wing-warping.