Ryanair is being accused of stopping some children flying to European Union countries from the UK based on made up rules.
The budget airline reportedly insists that EU laws state that a child's passport must be no more than five years old on the date of travel.
But other airlines and the European Commission (EC) are not aware of the existence of any such rule, according to The Independent.
The paper claims the Irish airline has invented the rule for children's passports which caused a British family's holiday to Tenerife to be delayed by 26 hours.
Zak Schoneville, 15, was not allowed to board Ryanair's flight from Glasgow Prestwick airport to the Spanish island on Monday May 2 because the airline said his passport had expired.
His mum Lisa said the Ryanair representative at the check-in desk told the family that her son was unable to travel because of Brexit and that passports were only valid for five or 10 years from the date of issue.
She added that the family requested, on several occasions, links to websites but nobody showed them any physical evidence that Zak was unable to travel.
The European Commission says that, on the day of travel to EU member nations, British passports must have been issued less than 10 years ago. A British passport must also have at least three months remaining before its expiry date on the day its owner plans to leave the EU.
Zak's passport was issued in March 2017 and has an expiry date of 31 October 2022. It was five years and two months old and five months away from expiring.
The teenager flew to Tenerife with his mum, dad and sister the next day on a Jet2 flight from Edinburgh and was granted entry by Spanish border officials without any problems.
In a statement given to The Independent, Ryanair said: "This UK passenger was correctly denied boarding in Glasgow Prestwick because his passport was not valid for travel to the EU.
“This teenager’s passport was issued in March 2017, and therefore exceeded its permitted five years validity for entry to the EU in March 2022, and was no longer valid for travel on 2 May 2022.”
Ryanair has been approached for comment.