The first flanimals to take to the air were the Blugs. Blugs are the most diverse class of Flanimal on the planet. They are also the most numerous, but there's still plenty of room because the sky is a big place.
Blugs possess segmented bodies, with wings, legs, insides and outsides. They also have a very nervous system. A central nerve cord runs from the legs and wings all the way throuh the body and up to the brain where it stops, has seconds thoughts, and runs all the way back.