Even though the human body could produce wings, they cannot fly due to weight and possibly gravity.

if one checks out an eagle against a humnan body the difference is simple:: eagle has spongy type bones, most dynamic for flight,& feather arrangement, and scopic eyes. Man does not. Eagles weigh not more than 20#..while Man.. forget it! Michelangelo made a flight machine yes.. but eagles fly with ease pumping the wings of a machine produce acing arms!

The mass of human beings is more when compares to birds . so its difficult to fly even though one has wings.