Fantastic creatures appear in myths and legends from cultures around the world. These beings take many forms. Some of them run, slither, swim or burrow. Many of them fly. As a paleontologist who studies fossil birds and pterosaurs (Habib) and an illustrator who designs creatures for books and films (Whitlatch), we are especially interested in the biomechanics of flight and how to portray flying beasts believably. We recently teamed up to produce a book on this topic called Flying Monsters: Illustrating Flying Vertebrates (to be published in 2021 by Design Studio Press), which covers both real and imaginary animals. In the pages that follow, we riff on three fanciful creatures depicted in the book and explain the science that lifts them up while grounding them in reality.