Hainan Air plans to buy 30 Boeing 787-9s worth $7.7 billion
The order would boost Boeing's 787 program backlog to 855 planes, and represents the biggest order this year for the jet.
The 787 is Boeing's most high-tech plane, with a carbon-composite fuselage and improved fuel efficiency. The 787-9 is a stretched version introduced last year that seats 280 passengers and has a range of 8,300 nautical miles.
Boeing did not immediately respond to a request for comment.
(Reporting by Alwyn Scott in New York; editing by Matthew Lewis)