The term 'Aquatic Flier' can be broken down into two crossword solutions: TERN (4 letters). A TERN is a type of seabird that is known for its long-distance migrations and its ability to fly over long distances. It is a member of the family Laridae, which includes gulls, skimmers, and auks. Terns are found in many parts of the world, including coastal areas, inland wetlands, and even some deserts. They feed mainly on small fish, crustaceans, and insects. They have a distinctive black and white plumage, and their wingspan can reach up to 1.5 meters.