Human guinea pigs prepare for 20-hour marathon flights

For decades, travelers have stoically endured jet lag as an unavoidable menace on long journeys. Now, as airlines push for record-breaking non-stop flights halfway around the planet, efforts to counter the debilitating symptoms are turning into a billion-dollar industry. Fresh insight into the physical and emotional toll of ultra-long haul travel should emerge this weekend when Qantas Airways flies direct from New York to Sydney. No airline has ever completed that route without stopping. At nearly 20 hours, it’s set to be the world’s longest flight, leaving the US Friday and landing in Australia during its Sunday morning. This will be more than an endurance exercise. Scientists and medical researchers in the cabin will turn the Dreamliner into a high-altitude laboratory. The aim is to see how humans hold up to the ordeal. <br/>