Answer:
I move without wings, Between silken string, I leave as you find, My substance behind.
At first, I am nothing. Add something to negate. Add again to oppose. Add again to find the time to draw. Add once more to find nobody at all.
What flies around all day but never goes anywhere?
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
What kinds of men are always above board?
It weighs next to nothing but no one can hold it for long. What is it?