Thousands of travellers have been stranded at Heathrow airport overnight, and hundreds more at Gatwick, as snow continues to disrupt much of the UK.
There will be no flight arrivals at Heathrow on Sunday and only a handful of departures, while many Gatwick flights are affected.
Problems persist at airports UK-wide, while the Met Office is warning of icy roads across much of England and Wales.
More heavy snow is expected in eastern Scotland and north-east England.
Up to 10cm of snow are expected in these areas, and up to 20cm in hilly areas.
Forecasters said the UK was hit by extremely low temperatures overnight, with most parts of the country struggling to get above minus 5C, while fresh snow fell in eastern Scotland and north-east England.
Hundreds of thousands of Britons had been due to fly this weekend, according to travel association Abta, which estimated that four million people expected to go abroad.
Heathrow airport told the BBC that "a few thousand spent the night in the terminals" but said just four short-haul and three long-haul flights would leave on Sunday morning. It hoped to be operational on Monday.
Stuart Gash, from Swindon, who had been due to fly to New York for a Caribbean cruise with his wife and two children, said UK airports seemed unable to cope at the first sign of snow.
He said: "There was no more than two inches of snow and yet the runway is totally covered. Why aren't they ploughing it, why aren't they gritting it, why aren't they salting it?".
Andrew Teacher, from Heathrow operator BAA, said it had invested more than £6m in the last year in technology to move snow and de-ice runways and that staff had been working through the night.
But he said: "There comes a point where you cannot do any more; when you're moving snow and it's freezing behind," adding that many planes had been frozen into parking spaces. BBC News
