I've been to Argentina a dozen times, but can't recall if this has been checked - does Argentina require evidence of a return or onward travel ticket when boarding in the US? Presumably there are pretty simple ways to travel out of Argentina (i.e., Buquebus to Uruguay for the day) that don't require a plane ticket. So far have a one-way ticket to Buenos Aires and wasn't sure if it'll be an issue that I won't have a return/onward ticket at the time I board.