Answer:
It flies when it's on and floats coming off.
What is the thing which, once poured out, cannot be gathered again?
I know a word of letters three. Add two, and fewer there will be!
What's black when you get it, red when you use it, and white when you're all through with it?
What get wet while drying
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.