AA has a pretty long history in EZE. Years ago they actually owned a significant share of AR and were tasked with helping run the airline but AR was nationalized so that relationship came to an end. From time to time AA operates five daily flights with three to MIA and one of those being a day time flight. Up until three years ago they also operated a daily flight to MVD on a 767 or 777, that was always a fun 25 minute flight on a
Nowadays with US management and their operational focus they are doing maintenance while the planes sit all day. Actually investing quite a bit in spare parts inventory and training.