Junkers Ju 87 Franco did know nothing of it and that it was ordered directly by the Luftwaffe. During the Catalonia Offensive in January 1939, the Junkers Ju 87 returned to Spain. On the morning of 21 January 1939, 34 Heinkel He 111, along with some escorts and three Ju 87B, attacked the Port of Barcelona, five days before the city was captured by the Fascists. 29 Republican fighters were defending the city. There were more than 100 aircraft operating over the city and, while a Ju 87 was dive-bombing a ship, a Republican Polikarpov I-15 pilot, Francisco Alférez Jiménez, claimed it destroyed
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