There is a new exhibit on Feathered Dinosaurs and the Origin of Flight, at the Arizona Museum of Natural History in
What's amazing are the life-size recreations - according to the Museum webpage:
Deinonychus (right) had ancestors that were capable of flying so it is a bird that had lost the ability to fly.
Cryptovolans (left), a four winged bird. The flight feathers on the hind legs gives Cryptovolans the appearance of being a bird equipped with four wings.