Originally Posted by
upinsmoke
AC has another anomaly going in it's favor which is the connection in YYZ. For anybody from other continents who want to connect to South America, they are able to transit at YYZ, while a connection in the US would mean having to get a US Visa and go through immigration/customs.
Not any longer. Starting March 15, 2016, visitors or transit passengers from other continents must obtain a Canadian eVisa when flying via YYZ or any other Canadian airport.
http://www.cic.gc.ca/english/visit/visas.asp