In PHOTOS: Travel chaos in frozen Europe

Heavy snowfall has paralysed air-services in Europe as tarmacs remained under thick white blanket, leaving thousands of travellers stranded during the busy Christmas season.

At Frankfurt airport in Germany, more than 700 flights remained grounded last evening as heavy snow and sleet on runways made take-offs and landings difficult.

No improvement is expected on Monday as snowfall continued in night, officials said.

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The airport is bracing for more stranded passengers after weathermen predicted further problems on Monday with up to 20 centimetres of snow falling in some places.

Airport authorities said even though snow-clearing teams struggled to keep the runways and aircraft snow free, cancellations and delays at other European airports also had a knock-on effect on the operations in Frankfurt.

An estimated 3,000 air-travellers have been stranded at the Frankfurt Airport, since the travel chaos began on Friday.

Many of them have been put up in hotels by their airlines.

"The entire flight plan at the airport is in disarray," officials said. Europe's busiest airport in London -- Heathrow -- stopped accepting arrivals on Sunday, causing havoc at the start of the Christmas travel rush with thousands of fliers stranded.

The British air-hub said delays and cancellations would spill into next week. Similarly, hundreds of passengers were forced to spend night at London's Gatwick Airport due to cancellations and flight delays.

At Paris' Charles de Gaulle and Orly airports, more than 40 per cent flights were cancelled and many passengers slept in makeshift dormitories.

Over 1,500 passengers spent their second night at the Brussels airport mainly because connection flights from London, Frankfurt or other snow-hit cities are not leaving.

Officials at Amsterdam's Schiphol airport said more than 1,700 beds were "far too less" for around 3,000 passengers stranded there and many of them had to sleep on sofas or on floor.

At Germany's second largest airport in Munich, around 50 flights were cancelled yesterday and around 200 stranded passengers spent the night on camping beds.

Flight delays and cancellations were also reported at the airports in Hamburg, Berlin and Hannover.

Several hundred stranded passengers spent the third consecutive night at Frankfort airport, sleeping on more than 1,000 camping beds, the officials said.

The officials said even if the airport returns to its normal operating schedule on Tuesday, it will take several days to clear the huge backlog of passengers built up in the past few days.

German airlines Lufthansa operated a contingency flight plan for its domestic and European flights, curtailing the number of flights taking off and landing in Frankfurt.

The airline said its new flight schedule, introduced on Saturday, will remain in force till Monday.

The German railways reported that its long-distance trains were operating, but some of them have been delayed.

It also warned passengers that the trains are overcrowded because many stranded airline passengers are taking its service to reach their destinations.

The country's railways too imposed speed restrictions for its high-speed express trains.