Flight SQ24, an Airbus A350-900ULR registered 9V-SGB, was carrying 144 passengers and 17 crew when it left Changi at about 12:24 p.m. on Sept. 14, Singapore Airlines said in statements.

Citing Flightradar24 data, AsiaOne reported the aircraft reversed course roughly four hours later while over the Philippine Sea off Taiwan, and landed back in Singapore at 9:11 p.m.

The airline has not said who fell ill, declining to give details on grounds of customer confidentiality.

Mothership cited posts on Reddit from people who said they were on board and that the captain was the one affected, with a doctor called forward during the flight. Singapore Airlines has not confirmed those accounts.

SQ24 is the eastbound leg of the world's longest scheduled nonstop commercial route, covering 15,349 km between Changi and John F. Kennedy International Airport in about 18 hours 50 minutes, according to Simple Flying's review of the carrier's schedule filings.

A Singapore Airlines Airbus A380 plane is parked on the tarmac at Changi International Airport in Singapore on Oct. 24, 2020. Photo by AFP

Passengers were given refreshments and other assistance on the ground while the aircraft was refueled, SIA told Mothership.

"SIA apologizes to all customers for the inconvenience caused," a spokesperson told AsiaOne.

The same jet pushed back at 11:58 p.m. and took off at about 12:12 a.m. on Sept. 15, Flightradar24 data shows. It reached JFK at around 5:37 a.m. New York time, roughly 10 hours 45 minutes behind schedule.