Looking to save the most money on your next plane ticket? A new survey by flight search engine Kayak.com says the lowest domestic flights can be found 21 days before your date of departure—make that 34 days before your departure date for international flights. Domestic airfares found within two weeks of departure increased by five percent, and were 30 percent higher one week before the departure date. The international airfares found 34 days prior to departure were four percent lower than flights booked six months earlier than the departure date.
The new findings come from compiling and analyzing one year's worth of search results data from an average of 100 million flight searches per month. Here's something counterintuitive; The results suggest that you should NOT book domestic flights too early, as those reserved six months before the departure date were 19 percent higher, and flights found five months ahead were 18 percent higher than flights booked 21 days before departure.
Which days of the week you fly also make a difference. When booking domestic flights that are up to one week long, Kayak found that the lowest-priced fares depart on Saturday and return on Wednesday, while flights longer than one week that depart on Tuesday and return on the following Wednesday have the lowest-priced fares. For international flights up to one week long, Kayak recommends departing on Tuesday and returning on the following Wednesday, or departing on either Friday or Saturday and returning the following Monday—for trips longer than one week, try departing on Saturday and returning the following Sunday, or aim for the second-cheapest set of airfares by returning on Monday, Tuesday, or Wednesday.