It is summer travel season, so we looked at the price trends leading to the Memorial Day holiday for the past few years. Historically, the ideal time to book a flight for the Memorial Day weekend is at least three weeks in advance.

Also, the best strategy to book a hotel for the Memorial Day weekend has been to wait three weeks before departure, but you can get a good price even the night before departure.

Our KAYAK users have been asking for tips on how to get a good price. Many experts will advise you to book as far ahead as possible, and make sure that it is at least 21 days in advance, or worst case at least 14 days in advance.

KAYAK gets millions of searches per day, so we looked at our data to put these ideas to test. We only analyzed selected prices, so the if there is an outrageously low price for a 3-stop flight none of our users selected, it will not be in these data.

It turns out that the reality (at least over the last two years) is bit more subtle. It does pay to book in advance, but not too early.

Prices generally drop until 15 days before departure, and then they start going up.
The cheapest average price is found exactly 15 days before departure for an average of $308.63.
The most expensive one is found 365 days before departure for an average of $513.14. In contrast, the average selected price for a same day departure is $366.86. So, on average, you are better off waiting to book the day of the flight departure, rather than booking a whole year early.

And generally it seems that our users have been finding the best prices between four weeks and one week in advance.

I am including a chart with the data below.

Are People Afraid to fly on Halloween?
If So, Can You Save Money On Flights When Other People Are Scared?

I ran a quick analysis of US flight search data over the past two years on KAYAK sites, to find out the flight pricing trends on Halloween.

I looked at average selected airfare prices on Halloween vs. the overall average for the past two years. Prices were 5% less on Halloween. That's not a massive difference, but across such a large sample, it's statistically significant. Then I looked at other dates when people might be afraid to fly - Friday the 13th and September 11th. I found an even bigger difference here - average selected airfare prices were 12-14% lower than the average for the past two years.

I think you can save money, if you travel when other people might be afraid to fly.