A marginally related question: Can I do international transfers in LIM on separate tickets? My friend is looking to fly NYC-Buenos Aires, and by far the cheapest business option is JFK-LIM on LATAM and then a separate LIM-EZE ticket (he'll probably fly Y on that leg). Would he need to clear Peruvian customs, or can he stay planeside?

I will urge him to do carry-ons only, but possible he checks bags. Assume, then, that LATAM lets him check them through.