At least 30 Heathrow flights have been cancelled, most of them on British Airways' European routes, due to heavy fog in Britain last night.
There were also six cancellations at Gatwick and six at London City Airport. London's other main airport, Stansted, was operating with delays.
With fog lifting and temperatures easing, airports that suffered flight chaos yesterday were operating near-normal services today.
But the knock-on effect due to the cancellations mean that some holidaymakers will be forced to spend Christmas in a hotel.
At Irish airports flights are taking off and landing on schedule.
