Since the 1950s the minimum width of an airline passenger seat has been set at 43.18 cm (17 inches). Based on sleep research by Doctor Irshaad Ebrahim of the London Sleep Centre, released by Airbus, it was found that passengers will get a better night’s sleep were they to travel in 45.72 cm (18-inch) wide economy class seats. Ebrahim who monitored twitching limb movements, brain waves and sleep behaviour found passengers would be less affected in wider seats. In 1998 no flight was over 7 000 nautical miles Since around 2008 flights over 6 000 nautical miles (over 13 hours flight time) has increased by 70 percent. According to current trends passenger air traffic will double and by 2032. The world’s airlines will take delivery of more than 29 220 new passenger and freight aircraft. Boeing has not commented.