Incorrect cost when flying with your animal. They do not charge the cost of what your flight is. It sound like you were not on the flight with the animal and flew him/her shipped as actual Cargo.

American Air: $150 US one way set rate.
(up to 100 lbs combined with Kennel. Large Kennel average weight 12 lbs.)

Continental Air: Fee figured based on weight of animal and kennel combined and a rate for distance traveled. To give you an idea for a pet and kennel totaling 90 lbs you're at approximately $450 one way.

US Air: Will not check animals internationally (they will allow small dog/cat at $100 fitting under the seat and count as a carry on to some destinations, check for details.)