Ryanair (RYAAY) is facing an investigation by the UK's Competition and Markets Authority over charges parents must pay to sit with their children on flights, the regulator said Thursday.

The CMA said Ryanair requires at least one parent to sit with children aged 2 to 11 through a mandatory family seat reservation, which typically costs about 8 British pounds ($10.7) per flight.

The regulator is investigating whether the practice could amount to an unfair contract term under UK consumer law.

The CMA said it is also examining whether Ryanair's booking process adequately presents the mandatory family seating charge as part of the total price paid by consumers.

Ryanair did not immediately respond to MT Newswires' request for comment.