Britain was hit by travel chaos on Thursday as much of the country was covered by a thick blanket of snow at the height of the morning rush-hour.
Hundreds of schools were closed and there were delays on trains, planes and roads.
Runways at Gatwick, Birmingham, Bristol, Cardiff, Luton and Stansted were closed for part of the morning while workers cleared the snow.
"Nearly 100 flights were cancelled," a Stansted spokeswoman said. "The runway has reopened but there is going to be a knock-on effect."
A Luton airport spokesman said there would be no departures until 12:30 p.m. or arrivals until 1:30 p.m. Passengers should check with their airline before setting off.
At Heathrow, 86 flights were cancelled, although the airport and its runways remained opened. Many flights were cancelled at London City Airport.
There were also cancellations and delays at Glasgow, Edinburgh and Aberdeen airports.
The Met Office said many areas will receive 2 to 4 inches of snow, although the wintry showers will ease during the day.
The Highways Agency warned drivers to check weather forecasts and road conditions before setting out.
The agency had put 400 salt-spreading vehicles on standby and all England's motorways and major roads were treated before the snow arrived.
Birmingham City Council said all its schools were closed due to the travel disruption. Dozens more were shut in Bristol, Cheshire, Gloucestershire, Somerset and Staffordshire.
Network Rail said the disruption was "minimal," although there were cancellations and delays across the southeast and on services run by Virgin West Coast, Virgin Cross Country, Chiltern and Central Trains.
Eurostar trains were unaffected by the weather, a spokesman said.
But there were severe delays and closures across the London Underground system. The Bakerloo, Jubilee and Metropolitan lines were among the worst affected.
The snow will peter out during the afternoon on Thursday but temperatures will plummet overnight to as low as minus 24 degrees Fahrenheit, bringing the risk of icy roads and freezing fog, the Met Office said.