Originally Posted by ak
AA doesn't allow carry-on pets to/from Hawaii or Transatlantic/Transpacific or Central and South America.
The aa.com web page you linked above is contradictory on this point ... the first part of the page lists South America as allowing pets in the cabin (and shows the fee for this service), while the bottom of the page states that it is prohibited. One of the two statements is wrong, but the top part is more likely to be correct as it seems to have been updated more recently.