Microraptor
Sankar Chatterjee found that, in order for Microraptor to glide or fly, the fore and hind wings must have been on different levels (as on a biplane) and not overlaid (as on a dragonfly). Using this biplane model, he calculated possible methods of gliding, and determined that Microraptor most likely launched itself from a perch, swooped downward in a deep 'U' shaped curve and then lifted again to land on another tree. The feathers not directly employed in the biplane wing, like those on the tibia and the tail, could have been used to control and alter the flight path. The hind wings would also have helped control the gliding flight.