Thousands of flights were cancelled around the world over the Christmas holidays as the highly infectious Omicron variant wreaked havoc on airlines, especially in the US.
More than 2,300 commercial flights were cancelled, around 800 of them in the US, on Saturday, according to the FlightAware tracking website.
A similar number of flights were axed on Friday.
US media reported that airlines had been hit by a shortage of healthy staff amid a spike in COVID-19 infections fuelled by the now-dominant Omicron strain.
A spokesperson for Delta Air Lines told the New York Times that “a combination of issues, including weather and Omicron-related issues,” were to blame.
United Airlines cited crew illnesses as the main cause of flight disruptions.
Despite early findings that Omicron is milder than other variants, scientists are concerned by the sheer number of infections being recorded.
Many of the flight cancellations are the result of airline crews testing positive, or being forced to self-isolate to stem the spread. “When we have millions and millions and millions of people, all sick, all together at one time, it doesn’t take a large percentage of those people to topple over the hospitals,” Dr Hallie Prescott, associate professor of internal medicine at the University of Michigan, told the New York Times.
In the UK volunteers are preparing for a Christmas Day booster jabs push to reduce the impact of Omicron.
Across Europe, governments are bringing in their own measures to combat the increase: Italy, Spain and Greece have made face masks compulsory outdoors again; Catalonia, in north-eastern Spain, has imposed an overnight curfew; The Netherlands entered a strict lockdown earlier this week.
Germany has said it will restrict private gatherings to 10 people and close nightclubs from 28 December.
Portugal has ordered bars and nightclubs to shut from December 26, and made working from home obligatory until January 9.
But in South Africa — where the Omicron variant was first identified — the government has ended COVID -19 contact tracing, except for serious cluster outbreaks or prisons. The health department announced that as most of the population had now been exposed to the coronavirus, the policy is now shifting from a containment strategy to one of mitigation including self-monitoring, mask wearing and social distancing.
The US had earlier announced it would lift travel restrictions imposed on South Africa and seven other African countries because of concerns about the Omicron variant on Dec 31.