Even with the growth of fare tracking services, price guarantees, and super-powerful flight search tools, it's hard to shake the nagging feeling that if you'd just timed your search a little differently, you'd have paid less for your flight.
Two economists have taken up the cause of calculating the elusive booking sweet spot and determined that the best time to purchase airfare is eight weeks in advance of your departure. As reported in the Guardian, economist Makoto Watanabe's research also suggests that flights are cheaper in the afternoons. (Incidentally, he compared the airfares to theater tickets, which tend to follow a different pattern and become cheapest at the last minute—on performance day.) In their report, Watanabe and his colleague Marc Möller write:
"When we book our flight to London weeks ahead we have to account for the possibility of unforeseen events which make our trip to London impossible. In order to make consumers take their chances, airlines have to offer advance purchase discounts. As a consequence, ticket prices increase as the travel date approaches."
This analysis sounds reasonable to me, but I'm not convinced that their eight-week rule will apply from one route to the next. It's not the kind of hard-and-fast rule that travelers might hope for—and no replacement for setting up fare alerts or checking predictions based on historic data for your specific route.
The Guardian published sample data on booking an EasyJet flight from London Stansted to Munich that supports the eight-week rule, with a cheapest price of £19.99, compared to two weeks in advance at £62.99 or 12 weeks in advance at £25.99.
But when I priced out a round-trip flight between New York City and London on Kayak.com—a longer-haul flight and with the added factor of comparing across various airlines—I found that the eight-week advance price of $661 on Virgin Atlantic was cheaper than the four-week advance price ($759, American), however slightly more expensive than the 12-week advance price ($632, Icelandair).
Then I tried nonstop routes on Kayak.com between New York City and Atlanta. The results showed that the cheapest point was to book four weeks in advance ($189, Airtran), rather than eight weeks out ($289, Delta), 12 weeks out ($309), or one week out ($209, Delta).
How does Watanabe's research compare with your own travel booking experiences?