Boeing has restarted wide-body jet deliveries to China that were halted in recent weeks due to a Chinese regulatory review which also stalled new narrow-body deliveries by the U.S. planemaker, according to flight tracking data and two sources.

New Boeing deliveries to China have been off and on since 2019 after two fatal crashes of MAX 8 jets and amid intensifying tensions over issues ranging from technology to national security between Washington and Beijing.

The resumption is a boost to Boeing, which had flagged the China delivery delay to investors, and which is engulfed in a separate safety and quality crisis.

On Friday a brand new Boeing wide-body 777 freighter registered to Air China Cargo as B-223S flew from Everett Paine Field in Washington state, where Boeing has a factory, to Beijing, according to flight tracking platform FlightRadar24.

Late on Sunday another new 777 freighter registered to Air China Cargo as B-223T departed Everett Paine for Beijing, tracking data showed.

Air China did not respond to a request for comment.

Last week that orders of wide-body 777 and 787 planes are expected to be delivered in the coming days, with 737 MAX deliveries set to resume as early as July.

China suspended most orders and deliveries of Boeing planes in 2019 after the 737 MAX was grounded worldwide after fatal crashes in 2018 and 2019.

Deliveries of wide-bodies re-started in December and narrow-body MAX jets in January. In late May deliveries had again stopped due to a review by the Civil Aviation Administration of China (CAAC) of batteries in 25-hour cockpit voice recorders.

Boeing directed a request for comment to CAAC, which did not respond.

In a year-end 2023 filing, Boeing said it had about 140 737 MAX 8 aircraft in inventory, including 85 aircraft for customers in China. Boeing delivered 22 aircraft to China between the start of 2024 and the end of April.

The planemaker estimates Chinese airlines will need 8,560 new commercial planes by 2042.