As early as 1915, Hugo Junkers was working on an all-metal low-wing aircraft. This innovative concept was rejected by the Luftstreitkräfte despite the duralumin structure that offered pilots relatively greater safety. Finally, the J.9 design was approved, designated D-I but only arrived to front line pilots in the last months of the war. Despite the qualities of speed and maneuverability, only 41 copies were built, in particular due to a difficult construction. This plane is the only extant example that survives today.

All-metal, except the propeller! Fighter pilots did not like it, but the D.I was the harbinger of a lineage of Junkers airliners.

This exhibit at the Musee de l'Air first flew in 1918. It is the sole surviving example of the type.

1918 fighter employing the Junkers corrugated metal construction.