Pterosaur, the winged reptile, is one of nature's great success stories. Often referred to as pterodactyls, pterosaurs survived as long as the dinosaurs but they are not dinosaurs. They spread across the globe, soaring or skimming over oceans, inland seas, lakes and rivers, where they became commanding predators of fish and other creatures. They diversified like mad and ranged from the size of a sparrow to that of an F-16 jet-fighter. But pterosaurs have long proved a mystery to scientists, ever since the first fossil was discovered in Germany in 1784. How did they catch and kill their prey? Did they lay eggs or give birth to live young? Did they walk on two or four legs? What was the function of the bizarre crests that made some of them look like revellers in a kind of Jurassic Mardi Gras? Perhaps most challenging of all, how did they fly? Their wing design and flight control were unlike anything that has been seen before. In Flying Sky Monsters, animation and CGI helps us look at these fascinating creatures in more detail. What did they eat, how did they live, why did they vanish? We travel to Inner Mongolia to both search for pterosaur fossils and to see if a team of palaeontologists, scientists, aerialists and engineers can reconstruct a pterosaur in order to establish how an animal that large flew.