Air Canada has been flying from Toronto (YYZ) to Buenos Aires (EZE) via Santiago (SCL) for several years, most recently 4x/weekly using 787-9's.
Effective 02May18, Buenos Aires Ezeiza (EZE) and Santiago (SCL) will both be served non-stop from Toronto (YYZ); Buenos Aires 3x/weekly and Santiago 5x/weekly, both with 787-9's. The reason for Santiago having more flights than Buenos Aires is that there is more business travel between Chile and Canada due to the very active mining industries in both countries.
One consequence of the new routings is the loss of the cheap one-way fares offered by Air Canada between Santiago and Buenos Aires and v.v. as a way of filling empty seats on these legs.
* Zurich (ZRH) - Buenos Aires Ezeiza (EZE) - eff 07Nov18 - 2x/weekly
Edelweiss is the leisure division of Swiss International Airlines and part of the larger Lufthansa Group of carriers. The new service will be operated with A340-300's, presumably because these aircraft are written down on the carrier's accounting books, appropriately lending themselves to low-fare tourist traffic.