AA does not have any 777-200s in domestic configuration, that is UA that does. AA's only domestic routes with 772s, AFAIK, are MIA-DFW/DFW-MIA, MIA-LAX/LAX-MIA, and DFW-ORD/ORD-DFW. To Latin America, out of MIA at least, AA uses the same 772s they use to Europe. The market between Miami and Buenos Aires is just like that between New York City and London. It attracts a lot of high profile customers, and is a big money maker. Currently, GRU has a daily 772 flight and EZE has two daily 772 flights, both from MIA. MIA-SCL, one daily MIA-GIG flight, and the second daily MIA-GRU flight are supposed to be going 772 by year's end. As a result, Asuncion, Paraguay, served via GRU (MIA-GRU-ASU), will go 777 as well, and possibly Belo Horizonte, served via GIG (MIA-GIG-BHZ).