Revealed: The cheapest days to fly, how far in advance you should book plane tickets for the best deal – and whether clearing your browser history really DOES land you better fares.Handy - to sleigh the least: EasyJet sets up special airport post boxes for letters to Santa - and will fly them directly to his home in Lapland.Why Nice is very nice in winter: With sapphire skies, affordable hotels and convivial restaurants, the chic French city is perfect for an invigorating escape without the crowds.