Otto Lilienthal, also known as the "Glider King", appears in the first episode where he snatches Yomiko's book while she is in the Library of Congress. The Library team chases him to New York City, where Yomiko builds a giant paper airplane to engage Lilienthal in aerial combat. Yomiko and Nancy defeat him by attaching a paper grappling hook to his glider, which then crashes into the Statue of Liberty.