Chaos at airports across the world, as thousands of flights have been cancelled on the biggest holiday weekend of the year. It comes as a surge in COVID-19 infections, driven by the Omicron variant, has brought greater uncertainty. More than 2,300 flights were cancelled on Friday, Christmas eve while over a thousand flights have been cancelled or rescheduled for Christmas day. In the U.S., two of the biggest airlines grounded hundreds of flights due to staff shortages. And in the UK, the prime minister, in his Christmas message, urged the public to get a booster shot. New cases are at record levels there, but Boris Johnson has decided against new curbs for the weekend.