I shipped my dog inside plane many times.
There are many cost included in it like:

Transportation to and from the airport.
Import permits and international health documents.
Airfare.
Pre-move vet visits.
Government endorsements.
Quarantine fees.
Travel crate.
Custom fees.

Therefore i prefer shipping my dog from dog shipping companies also. Mostly through Citizenshipper.
https://citizenshipper.com/pet-transportation