(FILES) This file photo taken on September 23, 2015 shows a Boeing 737 aircraft in Air China livery as Chinese President Xi Jinping (R, on podium) speaks beside Ray Conner (L), President and CEO of the Boeing Commercial Airplanes, and Dennis Muilenburg (2nd L), President and CEO of the Boeing Company, after his tour of the aircraft manufacturer's assembly line in Everett, Washington. China will become the world's first trillion-dollar aviation market as its expanding middle class takes to the skies in ever greater numbers, US manufacturer Boeing predicted September 13, 2016. The world's most populous country is expected to add more than 6,800 new aircraft to its commercial fleet worth $1.03 trillion by 2035, Boeing said in its annual China Current Market Outlook. / AFP PHOTO / POOL / MARK RALSTONMARK RALSTON/AFP/Getty Images