Prevailing wisdom says to buy plane tickets on weekends 50 to 100 days in advance, unless you’re flying during a holiday
Booking inexpensive plane tickets seems more like magic than an exact science for a reason; the days of dirt-cheap prices have largely disappeared, and you’ll pay a significant amount of money no matter when you book and what seat you select. However, it still helps to be armed with some information. Studies that analyze the past behavior of travelers to discover the cheapest days to buy domestic plane tickets are well intentioned, if sometimes confusing. The good news is that they do dig up useful information once in a while.
The wisdom as of 2015
An Airline Reporting Corporation study released in October 2014 indicated that weekends have replaced weekdays as cheaper days to book. In addition, the study showed that it’s best to buy plane tickets 57 days early, on average and that ticket prices stay the same 50 to 100 days before takeoff. However, the biggest takeaway from this study is that airlines have begun reacting to traveler behavior (more on this in the last section).
If you’re flying over a holiday such as Thanksgiving, you’re better off buying your ticket two to four weeks before you leave. Otherwise, your next-best strategy is to buy a good few months early, before the window of 50 to 100 days.
What to do
Don’t try to book fares only on weekends. Airlines still release low-cost fares on Tuesdays and Wednesdays. In fact, because airlines have begun reacting to traveler behavior, a new pattern of abnormal behavior–for instance, if business travelers start booking flights in large numbers on Saturday instead of Monday–can throw off prevailing wisdom.
Look for flights in the 50-to-100-day window before takeoff and look on weekends as well as weekdays. Set fare alerts as early as possible for price drops, and look for airfare sales.