Covid has disrupted holidays plans for many. More than 8,000 flights have been grounded over the long Christmas weekend that began on Friday. On Monday alone, 1,400 flights have been scrapped, with Chinese and US destinations being the worst hit. There have been more Covid-related flight cancellations globally as the week starts.

Airlines have said that the disruption is due to crews testing positive or isolating. All South Korea's Korean Air flights were banned by Hongkong for two weeks, after positive cases among some arrivals.

Airports in Beijing and Shanghai appear to be the worst affected, with nearly 300 cancellations combined. The Chinese authorities have not commented on the issue.

The worst hit US airline companies are United and JetBlue. Severe weather is also a factor for flight cancellations. A blanket of snow delayed flights and disrupted roads in the western state of Washington on Sunday, adding to the travel chaos.

In the UK, British Airways has 42 cancellations on Monday, as per data from FlightAware. London's Heathrow airport has 47 cancelled flights.

Meanwhile cruise ships were also hit by Covid cases while sailing in US waters. Several of them reportedly were denied port in the Caribbean, AFP news agency reports. An undisclosed number of passengers and crew aboard the Carnival Freedom cruise caught the virus so the ship was denied entry to Bonaire and Aruba, Carnival said in a statement. It was the third outbreak since last week affecting cruise ships operated by Carnival and Royal Caribbean departing Miami and Fort Lauderdale.