I reconstruct Aristotle’s explanation for why and how birds are capable of natural flight. For Aristotle, air is a markedly different external resting point in comparison with water and earth, and nature has designed birds so as to take advantage of the unique way in which air affects the inequality between the pushing downward, that is, the downward force and the resistance. My discussion sheds some light on Aristotle’s anticipation of some aspects of modern fluid dynamics and aerodynamics.