High Quality Content by WIKIPEDIA articles! Around 350 BCE, Aristotle and other philosophers of the time were attempting to explain the aerodynamics of avian flight. Even after the discovery of the ancestral bird Archaeopteryx, over 150 years ago, debates still persist regarding the evolution of flight. Currently there are three leading hypotheses pertaining to avian flight: Pouncing Proavis model, Cursorial model, and Arboreal model. Archaeopteryx, being the oldest known ancestor of modern birds, could provide clues to the origin of avian flight.