Aircraft have always been built of composites, from the Wright brothers' spruce-and-canvas Flyer to the de Havilland Mosquito's molded plywood fuselage in World War II. But the modern era began in the 1970s when engineers at Rolls-Royce and Boeing realized that carbon-fiber-reinforced polymers could be stronger than aluminum for the same weight. The Boeing 787 Dreamliner, introduced in 2009, is 50% composite by weight, including the fuselage and wings. The Cirrus SR20 and SR22, introduced in 1999 and 2000, brought composite construction to general aviation with a full-airframe parachute system as standard equipment. Composites allow for complex aerodynamic shapes that are impossible with aluminum, resist corrosion, and reduce fatigue. But they are not without challenges: damage can be invisible to the naked eye, requiring ultrasonic or thermographic inspection techniques. For pilots, the most important thing to know is that a composite airframe is not "repaired" in the traditional sense; it is restored by trained technicians using specialized processes that are as much art as engineering.