Originally Posted by
malmostoso
I think every *S card is basically useless outside of the airline that issued it.
Well, there are some niceties left in North America: For example, *S can check luggage free of charge on Air Canada (incl Express and Rouge). 1 or 2 pieces, I'd have to check.
Furthermore, on UA, *S get earlier boarding (some people love that), priority security screening (depending on the airport), and access to E+-seats that are not already taken at the time of check-in.