Heavy snow and cold, wintery conditions continue to sweep across parts of Europe, with the promise of more to follow by weather forecasters.
Charles de Gaulle and Orly airports in Paris were severely affected, with airlines scrapping 40% of flights coming in and out.
And French rail operator SNCF announced delays of up to 40 minutes as drivers reduced speed as a precautionary measure.
25,000 homes are also thought to have lost power in southwestern France, according to local reports.
Heathrow’s flight schedule has already been reduced to 250 fewer flights as it tries to cope with delays. But officials said that there might be 10% or more flights cut from Monday’s schedule, depending on conditions at other European airports.
The smaller Stansted and Gatwick airports were less affected but airport operators said delays and cancellations were likely.
UK weather forecaster the Met Office warned more snow was on the way for Monday. Ice warnings were issued for much of the country and people have been advised to take care as snow turns to ice on the roads and pavements.
The airports of Munich, Geneva and Frankfurt are also experiencing disruption and severe traffic jams have built up as drivers slow down on slippery roads.
Weather forecasts have predicted snow and sleet throughout the UK and other parts of Europe for all this week.