score:1
Meanwhile I've got response from Transavia's support:
For a baby of up to 24 months old, you may only take an infant car seat or umbrella buggy (a maximum of 7 kilograms) along with you on board of the plane. When you board the plane, transavia.com will load the infant car seat or buggy into the cargo hold. During the flight, you have to keep the baby on your lap. Each adult may only have a single baby on his or her lap during the journey. There are no carrycots on board.