According to a study conducted by CheapAir.com, the best time to book a flight is 54 days before a trip, reports The Huffington Post. However, this varies depending on the destination and time of year.
Overall, the study found that the prime window for getting the best deal on a flight is between 104 and 29 days beforehand. During this time, prices are likely to be close to the lowest fares for a given flight. Travelers visiting popular destinations at peak times or travelling long distances should generally book even earlier. For example, the best time to book a flight from the United States to Asia is 129 days before the flight. Booking at the last minute usually adds significantly to the cost of the flight.