Cathay Pacific flight CX 841 from New York to Hong Kong was diverted to Beijing as a passenger required urgent medical assistance, the carrier said.
There were 239 passengers on the flight, which landed in Beijing at 11:20 a.m. local time, Cathay Pacific said.
The diversion comes amid increased nervousness about terrorism globally after deadly attacks in Paris 11 days ago. Belgium's capital Brussels was on lockdown for three days, with schools closed and metros halted, as police conducted raids in and around the city, searching for suspects in the Paris attacks.
Concerns have also been raised after a Russian Metrojet plane crashed in Egypt last month, with a bomb suspected to be the cause. Islamic State terrorists have claimed responsibility for both attacks.
The U.S. State Department on Monday issued a global travel alert for U.S. citizens, citing increased terrorist threats, and extending into February of next year.
Since the Paris attacks, several other flights have been diverted. Last week, two Paris-bound Air France flights were diverted after the carrier received anonymous threats post-takeoff.
Flight A5055 from Washington to Paris landed safely in Halifax, Nova Scotia, while flight A5065 from Los Angeles to Paris, landed safely in Salt Lake City, Air France said.
Other airlines have also suffered threats. Singapore Airlines flight SQ001 from San Francisco to the city-state's Changi Airport. The plane landed safely, but both disembarkation and baggage collection was delayed.
Other events have also been cancelled due to terror threats. Last week, a soccer match between Germany and Netherlands was canceled at the last minute after authorities warned that a terror group planned to detonate bombs in and around the stadium. German Chancellor Angela Merkel had been expected to attend.