Kammala wannan jumla: Yaƙin Duniya na II a Turai ya fara ne a ranar Juma'a 1 ga Satumba 1939 lokacin da sojojin Jamus suka mamaye Poland. A lokacin, III. "Gruppe" yana karkashin umurnin "Hauptmann" (Kyaftin) Werner Mölders kuma an kafa shi ne a Wiesbaden-Erbenheim a ranar 26 ga Satumba, 1939. Kwamandan Müller tare da 8. "Staffel" shi ne "Oberleutnant" (First Lieutenant) Hans von Hahn. Müller ya tashi a cikin yakin basasa a lokacin yakin basasa kuma ya karbi Iron Cross 2nd Class () a ranar 17 ga Afrilu, 1940. Ya yi ikirarin nasararsa ta farko a cikin jirgin sama a lokacin yakin Faransa. A ranar 27 ga Mayu, 1940, yayin kwashewar Dunkirk, ya harbe wani Curtiss Hawk na Armée de l'Air a kusa da Amiens. A ranar 10 ga Yuni, an ba shi daraja tare da lalata jirgin saman jirgin saman Morane-Saulnier M.S.406 guda uku na Faransa. "Geschwader" ya tashi aikinsa na karshe a yakin Faransa a ranar 19 ga Yuni. A ranar 20 ga Yuni, III. "Gruppe" ya ba da kariya a kusa da Compiègne a lokacin yakin basasa.
An rattaba hannu kan yarjejeniyar tsagaita wuta a ranar 22 ga Yuni.