London (CNN) -- Passengers struggling to get away for the holiday season faced further frustration and delays Tuesday, as the EU's top travel official slammed snow disruptions across the region as "unacceptable." Heavy snow caused severe disruption to train and plane schedules in a number of major cities days before Christmas, forcing thousands of people to sleep in terminals while they waited for information on their onward journey. "I am extremely concerned about the level of disruption to travel across Europe caused by severe snow. It is unacceptable and should not happen again," European Commission Vice President Siim Kallas said in a written statement.
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NEW: Gatwick operations nearing normal, spokeswoman says
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BA considering transporting passengers by bus from Heathrow to other airports
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UK Transport Secretary lays blame for Heathrow chaos on "over-optimistic" operator
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Thousands of passengers await connections in European airports, rail stations
Heathrow
Heathrow
Kylie Deegennars said she had been sleeping on the terminal floor since arriving at @placeholder late Saturday.
Heathrow
Heathrow
@placeholder is to remain open for the next 24 hours, British Airways said, adding that it was considering bringing planes back overnight to clear the load.