How The Boeing 787 Dreamliner's Cabin Air Changes Long-Haul Comfort

Federal regulations permit commercial aircraft to maintain a cabin altitude of up to 8,000 feet (2,438 meters), and for decades most long-haul aircraft operated at or near that ceiling. Research published in the New England Journal of Medicine found that passengers in a hypobaric chamber simulating 20 hours of flight felt progressively worse as simulated cabin altitude rose across a range from 650 to 8,000 feet. Blood oxygen saturation falls by roughly 4% at the upper end. The limit was never set by physiology. It was set by what an aluminum fuselage could tolerate.