If you drop a buttered piece of bread, it will fall on the floor, butter-side down.
If a cat is dropped from a window or other high place, it will land on its feet.
But what if you tie a buttered piece of bread--butter-side up--to a cat's back, and then toss them both out the window?
Will the cat land on its feet? Or will the butter go splat on the ground?
Consider that (a) the laws of Butterology demand that the butter must hit the ground, and (b) that the equally strict laws of Feline Aerodynamics demand that the cat cannot land on its back.
Since nature would have no way to resolve this paradox, it just can't happen--the buttered cat construct simply does not fall!
Yes, this is indeed the secret of anti-gravity!
A buttered cat will, when released, quickly move to a height where the forces of cat-twisting and butter repulsion are in equilibrium.
This equilibrium point can be modified by scraping off some of the butter, to provide lift, or by restricting movement of the cat's limbs [using say, duct tape?--ouch!] to allow descent.
Most of the civilized species of the Universe already use this principle to drive their starships while traveling within a planetary system.
The loud humming heard by most sighters of UFOs is in fact the purring of several hundred cats.
There is one obvious danger, of course. If the cats manage to eat the bread off their backs they will instantly plummet.
Naturally, the cats will land on their feet, but this usually doesn't do them much good.
Since right after they make their graceful landing several tons of red-hot starship and pissed off aliens crash down on top of them.