I know not everyone is a fan, but just ask for Soda water if you are flying in SQ Y. You'll get that in a can (frequently the black Schwepps one).

On the other hand, I don't exactly know what the difference is between 'Soda' water they serve in Y and the sparking mineral water they serve in J. I've even googled the difference in definition but am not yet finding a definitive answer on this.