Answer:
I am a kind of coat that can only be put on when wet.
Never resting, never still. Moving silently from hill to hill. It does not walk, run or trot. All is cool where it is not. What is it?
I am lighter than air but a hundred people cannot lift me. Careful! I am fragile!
Upon your lonely journey I accompany you, whether you travel through endless mountains or seas of blue. Wherever you go, I keep your place. Lost you're not, when I'm embraced. What am I?
I have a strong affection for belly buttons.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.