The German High Command planned for a combined assault on Denmark to overrun the country as swiftly as possible, with an airborne assault on the Aalborg airfields and a surprise landing of infantry from naval auxiliaries at Copenhagen in addition to a simultaneous ground assault across the Jutland peninsula.
On 4 April, Admiral Wilhelm Canaris, the chief of the Abwehr and involved in the German resistance to Nazism, warned the Danes of an imminent invasion [REF].