According to the search results, the flavor of white mystery Airheads is not a specific flavor, but rather a mixture of leftover flavorings that couldnt make a full batch. The idea for the white mystery flavor came from a letter written by a teenager who suggested creating a "white bar with a mystery flavor". The flavor has been kept a secret to heighten consumer interest and to prevent extra flavored toffees from being thrown out. The absence of color in the candy allows for the mystery flavor to be easily distinguished from other flavors. In summary, the flavor of white mystery Airheads is a secret mixture of leftover flavorings that is unique to each batch.