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we know to create potential difference in pressure and proved in a wing shape, we can measure sound wave length, sound is pressure back and forth... do the math. it is really easy (at least in theory) if you understand the pattern and what energy is
 since surrounding nature experimented with this long before us easiest way is that must be checked feathers and snowflakes on birds... my bet is that one is producing some sound frequency and the other is using that sound to increase lift force... for this little "secret" birds are flying more efficient that us. insects also make some very constant noise... in natural word in terms of pray/predator it is very counterproductive but they did not adapted to do not make noise... this is because they need that noise and use it for power... to fly. my guess, noise is most energy efficient way to fly in atmosphere