The question I get asked more than almost any other is this: how far in advance should I book my airline ticket? 

The answer might surprise you. 

For domestic travel, the best window is between 21 and 121 days before departure. 

Book before that and the airlines haven’t posted the discounted fares yet. 

Wait too long and you’re going to pay a penalty. The sweet spot? The 60-day window. 

For international travel, that window is about 180 days in advance.