One needs to recall that on the scale of a bee, air density becomes an important factor. On a human scale, other considerations tend to "swamp out" air density for subsonic flight. Some people say that bees "swim through the air", which is a fairly decent metaphor. But not only can bees fly, they can fly and hover in even very low density air mixes, air densities that they would never encounter under natural conditons: http://jeb.biologists.org/cgi/reprint/198/4/1065 Yummy stuff in there - air density, wingbeat frequencies, stroke amplitudes, Reynolds numbers, lift coefficients... In short, it is clear that bees are better "aircraft" than they need to be, and that not only can they fly, they can fly under adverse conditions that would cause problems for many human-designed propeller aircraft and helicopters. (Jets are not a valid comparison, as they use pure brute force to fly, and without thrust, many have the "glide" capabilities of a brick.) And not to worry Adrian, the study cited was done without the use of even a single tax dollar! -- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---