Airlines will often be missing certain row numbers on their planes – look out for them on your next flight.

Many aircraft won’t use some numbers mainly due to old superstitions, with them being considered unlucky. Customers are less likely to want to sit in them so they’re discarded altogether.

Ryanair, Air France, Singapore Airlines, Cathay Pacific, Qatar Airlines, Emirates, KLM, Iberia and Lufthansa don’t have row 13s on some planes, according to Euronews.

This is due to triskaidekaphobia – fear of the number 13. The superstition is linked to bad luck, potentially stemming from stories of a bad guest at dinner.

Judas, who went on to betray Jesus, was the 13th guest at the Last Supper and Norse god Loki was 13th to arrive at the Valhalla feast, where he tricked another into killing the god Baldur.

Lufthansa leaves out number 17 altogether. The number is unlucky for some with the roman numeral XVII, its anagram VIXI roughly means “my life is over” in Latin.

The airline explained on its website: “In some cultures, the number 13 is considered unlucky. That is why there is no row 13 in planes, because we respect the superstition. That way nobody who thinks that the number 13 is unlucky has to sit in that row.

“In some countries, for example Italy and Brazil, the typical unlucky number is 17 and not 13. Seeing as Lufthansa welcomes a lot of international passengers, we try to consider as many of these specific cultural beliefs as possible.”

Many Chinese airlines omit row four from planes due to the Mandarin word for four sounding similar to the word for death. Buildings in China will often miss the fourth floor.

The 14th row is not included on some Chinese planes for the same reason. In Mandarin, the word for 14 is similar to how you say “is dead”.

It’s not just the airlines that avoid the number 13 – some hotels, cruise liners and property developers don’t have a deck, floor or house 13 either.