U.S. airlines expect a 5.2 percent increase in air travel during the Christmas and New Year’s break, to more than 2.5 million people a day.

The busiest day is expected to be the Friday before Christmas.

The trade group Airlines for America said Tuesday it forecasts that 45.7 million passengers will fly on a U.S. airline during the 18-day stretch that starts Thursday, Dec. 20, and runs through Jan. 6, the Sunday after New Year’s Day.

The group says that since last Christmas, airlines have added 143,000 seats per day on domestic and international flights. They are hoping that’s enough to handle the expected increase of 126,000 passengers a day.

Travelers looking for relative calm, take note: The least-busy days are expected to be Christmas Eve and Christmas Day.