From there Kayser travelled to Bergen, where he involved himself in the illegal press. After some time he decided to take part in secret military and sabotage operations. He escaped to England in September 1941, and enrolled in the Norwegian Independent Company 1 led by Martin Linge. Kayser was recruited from the regular training to the so-called Finishing School, where the emphasis was on secret agent skills. His first mission was the Operation Anklet in December 1941. In 1942 he planned Operation Woodcock together with Kasper Idland and Kjell Endresen, two other Norwegian Independent Company 1 soldiers. They were to parachute onto the Nevlandsheia plateau in Gjesdal and from there carry out a sabotage operation against the strategically important Sola Air Station in Western Norway. The team's first attempt to carry out the operation failed due to fog obscuring the drop zone. Further attempts were called off after a French sabotage team was intercepted by the Germans and explosives designed for the operation fell into German hands.