From MSNBC:
Scientists say dino-chicken used two sets of wings to flit between trees: Like the Wright brothers, the first flying dinosaurs took to the air with two sets of wings. New analysis of the winged Microraptor gui suggests that the first feathered dinos relied on a biplane-like wing configuration to swoop from tree to tree. The result may settle a century-old controversy over how the first feathered creatures achieved flight. “It is intriguing to contemplate that perhaps avian flight, like aircraft evolution, went through a biplane stage before the monoplane was introduced,” said Sankar Chatterjee of Texas Tech University. “It seems likely that Microraptor invented the biplane 125 million years before the Wright 1903 Flyer.”
More here.