Kawasaki Heavy Industries in Nagoya, Japan, where a forward section of the fuselage is built. Because the outer wall of the plane is so strong, the cabin can be pressurized more than in older jets. At cruising altitude, passengers will feel as if they're at only 6,000 feet, about the height of Colorado Springs. And because the composite skin doesn't corrode the way aluminum does, airlines can increase the cabin humidity to more comfortable levels.