I'd also like to point out that Helicopter engines can generate more "thrust" than their weight. Actually they seem to like to use watts as a power unit, but when you do the math the max amount of engine output is greater then the power of gravity.
Hmmmmmmm......
C'mon guys, somebody knows the answer to this question! (I don't)
See I'm fine with the fact that a 100 pound rocket producing 100 pounds of thrust will hover. So what's the excuse for most airplanes? F15 generates more thrust than weight, I've been told, so it makes sense to me that it can fly.