 To book your holiday flights now to get the best deal. Yep, according to experts, flights are going to be the lowest 71 days before departure this year as opposed to last year when it was 22 days before. And when it comes to the best day to book those flights, experts say booking Sunday will get you the best price while booking on Friday will hurt your wallet the most. After mid-October, flights are expected to rise and continue to go up significantly in the weeks leading up to each holiday. So get to booking!