User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-969093-20110713091450/@comment-1011548-20110713130205

All I can think of is that Amatsu has loads of sacs in his body filled with a lighter than air gas. Where he would get this gas, I have no idea. Also, he can channel air around his body with ease, so perhaps he is blowing lots of air out directly below himself... although that wouldn't work unless he was incredibly light in the first place.