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Yes royalty has had a lot of problems with inbreeding. Hemophelia is often called the royal disease, because it was passed on in British royalty for many generations.
Like others have said, an eagle keeping its wings stationary is just like your average airplane. The wings are curved in such a way that air passes over the top of the wing faster than it does the bottom of the wing. This creates low air pressure on top of the wing and high air pressure underneath the wing. Things move from higher to lower pressure, so the low pressure air is sucking the wing upward. The bird/plane is attached to the wing, so it gets sucked up too. This phenomenon is called lift. Airplanes are heavy, so they have to propel themselves forward in order to create a strong enough artificial wind over the wing to produce enough lift. Birds are light (hollow bones etc.), so natural wind is often enough to keep them aloft. If there's a lull, they have to start flapping.
Like someone mentioned, sails work on the same principle. I think somebody actually took an airplane wing, stuck it on a boat, and almost broke the wind-powered watercraft speed record.
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