Its a european company, i will look up the article link one moment . Plane has a separate part of the cabin where it house seperate 93 seats where only adults beyond 16 of age are allowed access to, for the extra premium of 40€ per seat.

https://www.bfmtv.com/international/europe/une-compagnie-aerienne-neerlandaise-introduit-une-zone-sans-enfant-une-premiere-en-europe_AN-202309010481.html

hope this is translatable cause its in french. maybe check their sales dept for info maybe, if the booking option doesn’t show up on their site