Wednesday's announcements, which came during Xi Jinping's first state visit to the U.S, underscored the intertwined interests of the world's largest planemaker and an aviation market on track to soon become the world's biggest.

"We are now proud to extend our partnership with a new, mutually beneficial collaboration," Boeing Chief Executive Officer Dennis Muilenburg told airline officials, employees and reporters gathered in a factory bay in Everett, Washington.

Boeing's ties in China date to 1972, when President Richard Nixon flew there in a 707 to thaw relations with the Communist country, Muilenburg said. China is Boeing's largest international market and a critical battleground in its tussle with Airbus Group SE to dominate the global jetliner industry.

Few Details

Details of the new agreements remain vague. The "general terms agreement" announced Wednesday covers orders and commitments for 190 single-aisle 737s and 50 wide-body jetliners, although models and customers weren't disclosed. Lessors ICBC Financial Leasing Co. and CDB Leasing Co. are taking another 60 737s. It's not clear how many of the orders already have been placed and marked as "unidentified" in Boeing's order book.

China is poised to displace the U.S. as the world's biggest aircraft and travel market in two decades, according to Boeing. It predicts airlines will need to add 6,330 new planes worth $950 billion by 2034 to keep pace with travel growth.

"The emerging middle class in China is helping to boost demand," said Mohshin Aziz, an analyst at Malayan Banking Bhd. in Kuala Lumpur. "Most of the planes ordered will be for growth, and very few will be for replacement."