Answer:
You see a boat filled with people. It has not sunk but when you look again you don't see a single person on the boat. Why?
I love to twist and dance. Though wingless I fly high up into the sky.
I lose my head in the morning and regain back it at night.
I am milky white and scares people.
With a halo of water and a tongue of wood; stone as skin long I stood.
I fly to any foreign parts assisted by my spreading wings. My body holds an hundred hearts Nay I will tell you stranger things when I am not in haste I ride and then I mend my pace anon.