We've just gone thru moving my mother's cats - twice. (Don't even ask.) This was on UA. UA charges $80 - and that might be per segment - or perhaps oneway. UA allows 2 cats per cabin. The cats must be in an approved carrier. They also require a vet bill within 15 days of the flight. The vet gave a sedative for the cats that my brother gave each before putting them in their cages. Thus the cats were quiet and groggy.

Call AA - you'll quickly get the information you need as to their requirements. I don't know where you turn as to what Argentina requires in terms of allowing pets in.