Zilly is a World War I Flying Ace, though it is clear that he would rather be anywhere than in the sky. As a Vulture Squadron member, it is his duty to fly in his plane and stop Yankee Doodle Pigeon from delivering messages to and from the enemy. Zilly describes himself as a chicken and a coward, due to his fear of flying. Whenever his superior, Dick Dastardly, would tell him, Klunk and Muttley to get into their planes, or whenever he says one of Klunk's inventions intimidates him, Zilly would always try to sneak his way out of going back into the skies, but almost every time, Muttley forces him to fly with the squadron anyway. The only time in the series where Zilly actually gets out of flying is in the episode "Movies Are Badder Than Ever".
When Don Messick performed the voice of Zilly, he gave the character a scared shaky voice which he speaks with in every episode. The only time he does not use this voice is in the episode "Zilly's a Dilly", in which he is hypnotized into being brave to the point of cockiness and "Tom Kenny" (SpongeBob SquarePants) is current voice for Zilly.
Connection to Klunk
Not only does Zilly work with Klunk as a flying ace under Dick Dastardly, but Zilly is the only one who can understand Klunk's gibberish language. Whenever Klunk would speak in his gibberish language, Dastardly would usually ask, What did he say? What did he say? It was then when Zilly would interpret Klunk's language. Zilly is the only character in the series who can understand Klunk.
- "Oh dear! Oh my!!"
- "Klunk says, 'We're ready to take off with another cartoon.' Oh dear...".