Audio By Carbonatix

Fridays that fall on the 13th day of the month get a bad rap. And it’s not exactly clear why. Friday lands on the 13th at least once every year. Some years, it happens three times. The world’s endured a lot of these unlucky days—yet they still send many folks into a tizzy.

The origins of a superstition

So how did this superstition start? Some say France’s mass arrest of the Knights Templar on Friday, October 13, 1307, kicked it off. Others argue that in early Christian—and even Norse—mythology, 13 was an unlucky number. And Fridays were unlucky days. So combine them and you’d better watch out. But one thing’s for sure: as long as there’s been mass superstition about Friday the 13th, someone’s been making a dime off of it.

In 1907, an author named T.W. Lawson published a novel titled Friday, the Thirteenth. The plot revolves around a broker shorting the market before creating a paranoia-based crash on a Friday the 13th. Since 1980, the Friday the 13th film franchise has made millions. But the latest Friday the 13th profiteers may be budget-minded globetrotters.

Flying on Friday the 13th

In 1972, Uruguayan Air Force Flight 571 crashed in the Andes. Many members of the rugby team onboard survived at 12,000 feet for over two months—a miracle that’s inspired multiple films. And of course, it went down on Friday, Oct. 13.

With so many Fridays falling on the 13th, the day isn’t statistically any more dangerous. But with the publicity surrounding Flight 571, that doesn’t matter. Many people just don’t want to board airplanes on this day.

The irrational fear of flying on this day even has a name: paraskevidekatriaphobia. So how many people share this fear? Enough to move the needle on plane ticket prices—in certain places.

How much cheaper are plane tickets on Friday the 13th?

The Sun reports that travelers flying out of London save 21% on average when traveling on Friday the 13th. The Kayak website crunched its flight data and found one of the cheapest destinations was Spain: flights from London to Gran Canaria dropped 44% for brave travelers.

So are U.S. fliers as superstitious? The data says “no”—or at least they’re willing to gamble a bit more to save a buck. Willis Orlando, flight operations manager at Kayak competitor Going, broke it down for Thrillist:

“While we might see a tiny bit of softening of demand departing from the U.S. for Friday the 13th travel, a quick survey of 10 popular domestic routes shows no noticeable pricing difference when compared to surrounding Fridays.”