Ever since Leonardo Da Vinci started scribbling designs for flying machines in his notebook, aviation has attracted bold, blue-sky thinking. Aviators continue to dream big: see Airbus’ sublimely odd design for a jumbo jet that mimics animal skeletons as a recent example. But since deregulation in 1978, airlines in the U.S. have done everything Da Vinci could have asked of them—except make money. Between 2001 and the end of 2008, for example, no less than 15 U.S. airlines filed for bankruptcy. Around 2008, however, something unexpected occurred. Airlines suddenly leveled off. In the past few years, profits have become positive across the industry, and market caps are soaring from prior lows.