Neither birds nor bats, pterosaurs were reptiles, close cousins of dinosaurs who evolved on a separate branch of the reptile family tree. They were also the first animals after insects to evolve powered flight—not just leaping or gliding, but flapping their wings to generate lift and travel through the air. Some were as large as an F-16 fighter jet, and others as small as a paper airplane.
Over time, the earliest pterosaurs—relatively small flying reptiles with sturdy bodies and long tails—evolved into a broad variety of species.