Some four million people from the UK are expected to travel abroad during the Christmas and new year period, according to a travel organisation.
The Association of British Travel Agents (Abta) is predicting that December 18, December 23 and December 30 will be the busiest travel dates.
Many airports are expecting an increase in passenger numbers from December 18 to January 2 compared to last year, with 900,000 departing from Gatwick, 500,000 from Stansted and 400,000 from Manchester.
Some 600,000 will fly out of Heathrow between December 19-25.
Hundreds of thousands of people will travel across the Channel by either ferry or train, with Eurostar predicting its busiest day will be on Friday.
Many people are taking a break within the UK, with strong bookings reported for city breaks in London and York as well as trips to Christmas markets around the country.
Abta chief executive Mark Tanzer said: "Christmas and new year is one of the busiest times of the year for travelling and holiday-taking and we will see large numbers heading off in the next few days.
"Hundreds of thousands will be flying off to visit friends and families but millions will also be heading overseas for winter sun or snow. Many will also be looking to welcome in the new year in cities around the world which really know how to throw a party."