United, which restarted flights to China in July, has abruptly reverted its sole San Francisco to Shanghai service to first stop in Seoul.

The Star Alliance member initially resumed nonstop service on the route in October with four weekly flights.

“Due to changes in operating conditions, we adjusted service between San Francisco and Shanghai to now include a stop in Seoul, South Korea, for a crew change as we did earlier this year,” said United in a statement to Business Traveller.

Lengthy waits for testing on arrival, concerns with government-designated hotels, and restrictions on movement are just some of the many challenges facing airline crew operating flights to China, according to CNBC.

By scheduling a stop in the South Korean capital to swap crew, United is able to circumvent on-arrival testing and overnight stays in China for pilots and flight attendants.

Passengers remain onboard during the 90-minute stop; however, journey time has been lengthened by about two hours and 15 minutes each way.

Delta, which restarted nonstop flights to Shanghai from Detroit and Seattle this week, told Business Traveller it has not yet announced or made any changes. The Skyteam carrier previously routed services through Seoul when it resumed flights to China in June.

Meanwhile, American Airlines said it would like to resume nonstop flights to the country but does not have a timeframe yet. The airline will continue to operate through Seoul for the foreseeable future. The carrier restarted Dallas to Shanghai flights in November.

International flights to China remain high in demand due to flight frequency and capacity restrictions to control the spread of Covid-19. Airlines are also subject to route suspensions if multiple travellers test positive on arrival.

“Due to capping seats in all cabins and government restrictions on the number of flights we are authorised to operate to China, near-term seat availability is extremely limited. We apologise to our customers for the inconvenience,” said a notice on Delta’s website.

united.com, delta.com, aa.com