The Cloud Roads, by Martha WellsRead about the other books on the list.
Like many flying islands and cities, those in the Three Worlds, home to Wells’ Books of the Raksura, are buoyed by magical rocks. Naturally, some of the (many and varied) earthbound humanoids have harnessed their power (the rocks retain their anti-gravity properties even when removed from the islands) to power flying boats. Moon, a Raksura (a race of shapeshifting humanoids) without familial ties, is ostracized by his adopted tribe, and his quest for a place to call home sets him off on a series of grand adventures.
--Marshal Zeringue