The S on the Heroscape cards?!

[Dominic]

At the bottom of the Heroscape cards (By which I mean Marvel/DC cards by Greywolf) there's a "wing" symbol w/ an "S" symbol.

I understand the "wing" symbol means flying, but what does the "S" symbol signify?

I assume "strength" but if that is so how do you play that?

[Sherman Davies]

Welcome to the site!

The S signifies that the figure has super strength, as per the Marvelscape rules. Basically, characters with super strength take no falling damage.

[KingArthur1976]

And destructible objects that normally get automatic shields do not get them vs Super strength characters.

[IAmBatman]

This might be more of a question for the customs section. I'm not sure if you're talking about the independent "S" symbol that rests alongside the wing (in which case the above answers are correct) or if you're talking about the "s" which is actually inside of the wing on a few cards.
If you're wondering about the latter, then it's a way to distinguish between regular flying and stealth flying, with the "s" standing for stealth.