“Unaccompanied minor” service is allowed only for children from 5 years old, but the upper limit of age can be different depend on airline: KLM - up to 14 years, Lufthansa - up to 11 years and etc. This service can’t be ordered online, you must contact your airline or authorized agency to specify all information.
Attention! 'Unaccompanied minor” service can be provided only if your entire flight is operated by only one airline - one you have ordered this service.
The parent/guardian must provide guarantee that they meet their child at the destination airport. The airport employee can hand the child after the passport of person who meets the child, will be represented.
If a child, for whatever reasons, will not meet, the airline has the right to make a decision about how to resolve this situation, parents/guardians pay for all these actions - it signed a special contract between the airline and the parent/guardian.
Most airlines provide access to special children's facilities or to the VIP-halls. Parents are usually should not leave the airport until the departure of the aircraft.