Some things to think about for maybe another synopsis idea is Final Fantasy 12 where a group of heroes band together to rise up against a war between two empires. The main character Vaan wants to be an adventurer and meets sky pirates Balthier and Fran. I now have thought about a story set between two warring kingdoms one of humans and one of monsters where after a band of Monster sky pirates board a supply ship a war is waged between the kingdoms. I'll do more thinking in to this idea but it's a sound idea.
Sky Pirates of Valendor -
A webcomic which may be of use to look into for ideas -
Sky Pirates of Valendor recounts the adventures of Pirate Captain Tobin Manheim and the rest of the crew of the Rogue’s Revenge. Set in the fantasy world of Valendor where giant continents float on oceans of sky! A mix of steampunk and high fantasy where magic co-exists with futuristic technology, Valendor is a fully realized world, with complex social structures, a guild-driven economic system, and a host of political intrigue.
Sky Pirates of Neo Terra -
I came across a comic based on a game being released on the Nintendo DS to do with sky pirates who are in a great race. The world is inhabited by tribes who have come after the world before was destroyed. This could be an idea to look into as a third synopsis idea was concerned with looking into the idea of a world after an apocolyptic devastation.