Fog is continuing to disrupt flights at Gatwick Airport with restrictions imposed to maintain safety.
On what is expected to be the airport's busiest day of the Christmas period, it said some flights "may be delayed throughout the day" due to "poor visibility" and apologised to customers.
While the weather is improving, the UK's main air traffic control provider Nats said temporary air restrictions are still in place for some airports in London.
Hundreds of flights have already been cancelled and delayed across some of the UK's major airports since Friday, with passengers still advised to check their flight before travelling.