Answer:
It flies when it's on and floats coming off.
What can be measured but not seen?
White bird, featherless, flying out of paradise. Flying over sea and land. Dying in my hand.
What gets wetter as it dries?
Inside a great blue castle lives a shy young maid. She blushes in the morning and comes not out at night.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.