Cloud Cat

The cloud cat (Aeluropteryx navigans) is not a cat at all. In fact, it is not even a placental mammal--it is a volaticothere. Volaticotheres were tree-shrew-like gliding mammals that lived during the Mesozoic. In our timeline they were completely wiped out alongside the dinosaurs, but in the world of Airborn a group of volaticotheres that had evolved powered flight managed to survive. Like the platypus, volaticotheres are egg-laying mammals. However, in the flying species the babies are kept inside a brood pouch until they are big enough to fly, explaining why they seem to give birth in the air. The cloud cat--the last and largest of its lineage--has simply taken this trait to its logical conclusion.

Airborn belongs to Kenneth Oppel