Junkers Ju 87 near Sagan, 13 Ju 87s and 26 crew members were lost when they crashed into the ground almost simultaneously. The planes dived through cloud, expecting to release their practice bombs and pull out of the dive once below the cloud ceiling, unaware that the ceiling was too low and unexpected ground mist formed, leaving them no time to pull out of the dive. On 1 September 1939, the Wehrmacht invaded Poland, triggering World War II. "Generalquartiermeister der Luftwaffe" records indicate a total force of 366 Ju 87 A and Bs were available for operations on 31 August 1939. The first
Hugo Junkers communist activist, as Managing Director of what remained of his business. Hugo Junkers is mainly known in connection with aircraft bearing his name. These include some he reluctantly developed for the German Empire during World War I, later in minor association with Anthony Fokker, as well as civil aircraft designs during the "interwar period" produced by "Junkers Flugzeugwerke" (Junkers Aircraft Works). Junkers died in 1935. The earliest all-metal post-World War I aircraft designs of both Andrei Tupolev — with his Tupolev ANT-2 two-passenger small aircraft of 1924 — and William Bushnell Stout's initial all-metal design, the Stout ST twin-engine torpedo