I fly the American Airlines monthly on either the EZE-MIA or EZE-JFK route, always in Business or First. AA only flies 772 aircraft on these routes whereas Delta and United fly 763 aircraft; over the next year or so AA will be refurbishing these 772 planes in a way that will benefit Business class customers but will make the trip more miserable for Economy class customers (business going to all aisle access flat beds, economy going from 9 across to 10 across, reducing width) One of the flight attendant crews on the twice-daily EZE-MIA route is always an EZE based crew consisting entirely of Argentines who are not employees of AAL corporation and are payed in AR pesos according to local prevailing wages. If you are a EZE based high level frequent flyer (100k+ eqm/eqp per year) American Airlines is currently your best bet because of their own FF program and their partnership with LAN/TAM.
FYI currently 98.3% of Argentines applying for the B1/B2 tourist/business visas are accepted. It has never been easier.