Their main difference is in conditions for the acceptance of pet, costs, and whether the passengers will travel on the same flight as their pet or not.
Luggage
If pet exceed the maximum size or weight allowance to travel in the cabin or the airline does not accept pets in cabin, you can also transport your pet safely in the luggage of the airplane. Check-in and reception shall be made by the passenger and the arrangements are made with the airline at the time of buying a ticket. The costs are usually more than the cost of transporting pets in the cabin but less than the cargo.
Cargo
If pet owners do not intend to fly with their pet, they can use the cargo to transport pets. Arrangements for the presence of pets in cargo are made by the cargo offices of the airlines. Transportation cost in cargo is more than cabin or luggage. It is worth mentioning that a pet must travel as cargo if the destination is a country such as Australia, Britain, UAE and Hong Kong.