WATCH: Hundreds of travelers spent the night in airports waiting for their canceled flights to be rescheduled after unexpected snowfall paralyzed major air hubs (video: Reuters).
Fresh snowfall is causing more misery for Christmas travelers in Europe with airports in London, Paris, Frankfurt, Amsterdam, and Brussels continuing to cancel flights.
Angry travelers are struggling to get to their destinations by Christmas amid a backlog of thousands of passengers who have been forced to sleep on terminal floors for up to three days.
The European Commission today said the travel chaos caused by the failure of airport officials to prepare for heavy snowfalls this week was "unacceptable."
European Transport Commissioner Siim Kallas said he would convene a meeting with airport officials in the coming days to "take a hard look" at ways to improve the situation.
Kallas said that new airport regulations due to be published before the summer could include new requirements on "minimal services" airports must provide during severe weather.
Kallas's statement comes amid calls in Britain for an investigation into BAA, the private company that operates London's Heathrow Airport.
London's Heathrow airport -- the busiest in Europe -- has been operating at one-third normal capacity, but the BBC reported that airport operator BAA turned down Prime Minister David Cameron's offer of troops to help clear runways.
Because Britain is outside the Schengen zone, the passport-free travel area within Europe, many passengers did not have the necessary visas to leave the transit lounge.
Eurostar, which links England to France and Belgium by train, also advised passengers to cancel their trips in the coming days and receive a full refund unless travel was absolutely necessary.
BAA and the private Spanish firm that controls it, Ferrovial, are accused of failing to make adequate investments on snow-removal equipment needed to keep an international transport hub operating smoothly through winter storms.
compiled from agency reports