However, the flight number is now being changed as part of an overall reordering of flight data by the airline.
What's more, the flight departed 20 minutes after the 13 hour of the day, but today's flight will be the last of 21 times FinnAir has flown the route on Friday 13 since 2006. In fact, it's been done 21 times in 11 years, all without incident.
But the airline is changing its flight numbers, which means it was AY666's last Friday the 13th trip to HEL.
If you feel like you missed out on a unique opportunity to take an "devilish" flight, rest assured, Finnair's got you covered with a flight from SIN (Singapore Changi International) to HEL. Pilot Juha-Pekka Keidasto said, "It has been quite a joke among the pilots".
For the last time, Finnair Flight 666 flew to HEL on Friday the 13th.
But for flying professionals, the flight with the bravest passengers in the sky is just another day at the office.
The fear of the number 666 is hexakosioihexekontahexaphobia. "It's only a coincidence for me".
Additionally, Finnair revealed that this isn't the first time they've journey to Helsinki aboard AY666 on Friday the 13th.
The final destination for passengers on this Friday the 13th flight is HEL.