With Singapore once again open to U.S. travelers, United Airlines on Wednesday announced that it will resume flights between San Francisco and Singapore beginning Jan. 5, 2022. The service will be in accordance with the Singapore government's Vaccinated Travel Lane program, which requires passengers traveling to Singapore to be vaccinated against Covid-19. United will operate four weekly flights from each city with a Boeing 787-9 equipped with Polaris and United Premium Plus cabins.