Junkers setbacks with crashes of prototypes in 1937 and 1938. Further refinements enabled certification in 1939 and spurred South African Airways to make an initial order for two aircraft fitted with US-built Pratt & Whitney engines. Just as the aircraft was being readied for its first commercial flights, World War II began. With the outbreak of hostilities, all models were requisitioned by the Luftwaffe for military air-transport roles, and later, long-range maritime patrol. Military aircraft production was begun by the company in the 1930s and eventually monopolized all its resources. Perhaps the most notable design was the Junkers Ju 87 "Stuka"
Junkers D.I Junkers D.I The Junkers D.I (factory designation J 9) was a monoplane fighter aircraft produced in Germany late in World War I, significant for becoming the first all-metal fighter to enter service. The prototype, a private venture by Junkers designated the J 7, first flew on 17 September 1917, going through nearly a half-dozen detail changes in its design during its tests. When it was demonstrated to the "Idflieg" early the following year it proved impressive enough to result in an order for three additional aircraft for trials. However, the changes made by Junkers were significant enough for the firm