Thousands of travellers at London’s Heathrow airport are crossing their fingers that heavy fog disrupting their Christmas plans will finally lift today. After three days of cancellations and delays, officials say conditions look set to improve. British Airways says it hopes to fly 95 percent of customers in and out of Heathrow as planned today. Mini-buses and coaches have been used to get many domestic travellers to their destinations. But it has been misery for others. While hotel rooms have been offered to thousands, many more have had to camp out at the airport. Jumbo jets have been brought in on some European routes, to try to increase the chances of people caught up in big backlogs of getting home for Christmas.