In the early 1930s KU experienced a major increase in membership and peaked at more than 30,000 members under the leadership of chairman Jack G. Westergaard. KU became somewhat of an institution by being the first non-leftist organization to use 'modern campaign methods', such as posters, pamphlets, marches, demonstrations and gatherings. Hosting open-air meetings with thousands of participants, demonstrating in the parks of Copenhagen, and flying over Copenhagen in propeller airplanes with conservative air leaflets became the trademark of the organization. One such incidence, when Copenhagen was plastered with thousands of campaign posters in a single night - is this day commemorated in the official KU song.