Junkers Ju 87 with several auxiliaries. The Polish naval units trapped in the Baltic were destroyed by Ju 87 operations. Once again, enemy air opposition was light, and the "Stukawaffe" (Stuka force) lost 31 aircraft during the campaign. Operation Weserübung began on 9 April 1940 with the invasions of Norway and Denmark. Denmark capitulated within the day; Norway continued to resist with British and French help. The campaign was not a "Blitzkrieg" of fast-moving armoured divisions supported by air power as the mountainous terrain ruled out close Panzer/Stuka cooperation. Instead, the Germans relied on paratroops transported by Junkers Ju 52s and specialised ski
Junkers marked on the J-9's landing gear wheel covers. The corrugated duralumin wing and fuselage "skin" introduced in the J-series became a trademark of Junkers aircraft built in the 1920s and '30s. Development continued during the course of World War I, including a growing (but troublesome) partnership with Fokker, as the "Junkers-Fokker Aktiengesellschaft". Several Junkers designs were licensed to Fokker during this period. The visual similarity of Junkers and Fokker aircraft during the next decade, especially after Reinhold Platz adapted some of the Junkers design concepts, but mostly crafted in wood for the Fokker designs' wing structures instead of the all-metal