The episode begins with David Attenborough explaining how insects had the skies to themselves for millions of years - when a pterosaur suddenly arrives on the scene and eats a dragonfly. David Attenborough tells the viewers that the pterosaur's name ... (more)is Dimorphodon. He travels back in time and watches the pterosaurs evolve into truly humongous behemoths like the late Quetzalcoatlus. Some pterosaurs even sported colourful crests that could have been used to attract mates. However, the pterosaurs had to share the skies with some remarkable flying dinosaurs like Microraptor. From these feathered flyers evolved the birds, who survived the K-Pg mass extinction. Some, like the swans, could gracefully fly at 30mph as David Attenborough shows when he tracks their progress on a boat. But then the mammals managed to lift themselves up, like the nocturnal bats. The battle between the birds and the bats for aerial supremacy soon began, and David Attenborough says that in the concluding episode, he will study the Aerodynamic War.