While there is no "magic" day of the week that guarantees the lowest price, recent data suggests that is statistically the cheapest day to book both domestic and international flights . Booking on Sunday instead of the most expensive days (Monday or Friday) can save you an average of 6% domestically and up to 17% internationally . The Best Days to Book vs. Fly
For last-minute travel, it is critical to distinguish between when you click "buy" and when you actually take off. Best Day And Time To Buy Plane Tickets - Forbes best day to buy last minute airline tickets