When Pigs Fly

If you've ever used the phrase "when pigs fly" to describe something that'll never happen, you may want to reach back into your bag of idioms. A team of flying experts has tackled the challenge of designing a pig that can actually take to the skies. To them, nothing is impossible. See the unique aerodynamics needed to get things in the air and unusual flying machines that look like doghouses, lawn mowers, and pigs.