David Biello in Scientific American:
In the 1930s French scientists determined that bees could not fly. They knew, of course, that the insects could and did. But according to their calculations, this feat was aerodynamically impossible. They based that conclusion on the fact that wings as small as a bee’s could not possibly produce enough lift to allow the bee to get airborne. The problem was, they presumed that the bee’s wings were stable, like an airplane’s, when in fact honeybees flap and rotate their wings 240 times a second. This flapping, along with the supple nature of the wings themselves, allows a bee–or any flying insect, for that matter–to create a vortex that lifts it into the air. But the specific aerodynamic mechanics of that process as it pertains to the honeybee, with its stubby wings, has remained a mystery until now.
More here.