Check with the airline at the time of booking, as there may have quotas on all flights or restrictions, according to destinations (vaccines, quarantine ...).
In the cabin : weight <5kg - In a cage specially provided for this purpose for animals not exceeding 5 kg (birds, cats, dogs), subject to the laws in force in the country of destination.
In the hold : in a cage for this purpose for animals of more than 5 kg. The rate is usually priced baggage fee. The discount applies in principle to transport in the cabin and in the cargo hold of passenger service dogs with disabilities.