Planning to book a flight to travel to see family over the holidays? Brace for another new charge for your flight. Yep, most of the biggest U.S. airlines have added one more fee on top of the pile of others you’re paying these days. The good news is it just affects a couple of days. The bad news is those couple of days are some of the most traveled all year long.

If you book a flight on November 29, January 2 or January 3, plan to pay the newly-added “peak travel surcharge” of $10 each way for domestic flights. At this point, the fees are being charged by American, United, Delta, Northwest and U.S. Airlines. The surcharges are built into the advertised fare the airline provides, so it does not impact the price you see. But know that it’s there, and by booking around those dates, you can shave off that extra $20, which may mean you can squeeze one more gift onto your shopping list.