Some people would avoid flying altogether on Friday the 13th.
But some people wouldn't mind. In fact, some would book a trip with the flight number 666. And the hardiest few would book that flight straight to HEL.
Today is the last day that Finnair's flight 666 will go from Copenhagen to Helsinki, having launched in 2006. The route will still operate, but under a different number from now on. The airline declined to comment on whether the change had been made with concerned or superstitious passengers in mind.
"We are a growing airline and we are reorganising our flight numbers to make room for additional flight numbers to be used," said a spokesperson for Finnair.
Four years ago (when flight 666 flew to HEL on Friday the 13th in the 13th year of the century. Yikes!), pilot Juha-Pekka Keidasto said: "It has been quite a joke among the pilots. I'm not a superstitious man. It's only a coincidence for me."
Superstition about Friday the 13th is thought to date back to the Middle Ages, when it was believed that Christ was crucified on a Friday 13th. There's even a word for the fear some people have about the day: paraskevidekatriaphobia.
Read more: Would you buy a flat on Friday 13th?