The crow-sized microraptor, dubbed dromaeosaur, was a carnivorous dinosaur that hunted in the forests of China 130 million years ago, they said.
Paleontologists had been puzzled why the tiny dino had a body built for running but also sported four wings and a long, feathered tail.
Anatomists say they think its configuration allowed the dinosaur to be a master of control, and its hind wings would have let it turn on a dime as it glided or flapped through the air.
"In terms of aerodynamics, the hind wings would have increased its rate of turn by 33 to 50 percent, compared to using only the front wings," Michael Habib of the University of Southern California said.
Habib and his colleague Justin Hall of the Natural History Museum of Los Angeles County presented their findings on dromaeosaur's flying skills last month at an annual meeting of the Society of Vertebrate Paleontology in Raleigh, North Carolina, National Geographic News reported.
Any improvement in turning speed would have been a "massive advantage" in the flying dinosaur's eat-or-be-eaten world, they said.
"This was an animal about the size of a crow, living among predatory dinosaurs at a time when the largest animal in the air had a 15-foot wingspan!" Hall said. "So, a 33-percent increase in turning speed could have meant the difference between life and death."