For humans trying to achieve flight, why hasnt the "big bird wings, and flap em really fast" approach worked? With enough physics and the proper bird wings, why cant I literally "make like a bird" and fly over to my friend's house?

If we're too heavy, bigger wings and an engine to flap them? Pterodactyls flew though, and they were big...

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http://xkcd.com/435/ For levity, how does this make you feel?

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A Mososaurous weighing 20tons (evenly distributed, lets say) and measuring 17m in length lives in a lake at a theme park. He swims into the audience viewing area, jumps halfway out of the pool to feed, and then falls back into the water.

Not unlike this: https://www.youtube.com/watch?v=Zv8qID-89ts

How big a splash/wave would the mososaurous have caused? (Height, distance traveled, and tons of water maybe?)