 Complete the following phrase:  When Germany invaded Denmark on 9 April 1940, the German Luftwaffe Air Force launched one of the first airborne operations in history, in which paratroopers captured the airport. Aalborg Lufthavn was considered a crucial element in the ferrying of troops and equipment from Germany to Norway as it acted as a refuelling base for Luftwaffe transport planes, especially a hrefJunkers20Ju20523mJunkers Ju 523ma, during the 