Amulet: Book Three The Cloud Searchers by Kazu Kibuishi
After a harrowing battle in Book Two, forces are scattered. Elf Prince Trellis is on the run from his oppressive father. The Elf King hires Gabilan the Assassin to go after both Trellis and Emily, the heroine of the story. Emily is reunited with her family but they decided to abandoned their house (the one that can walk around on its own) because it is too conspicuous. Her group winds up hiring an airship to go to the semi-fabled city of Cielis. Cielis was the home of the Guardian Council, a group of Stonekeepers who ruled the planet in peace and prosperity for many years. The Elf King rose up against them and pillaged the city, which has disappeared. Some think it wasn't completely destroyed and that a remnant is ready to fight back against the elves. The trick to confirm the story is that the city flies in the air--hence the need for an airship. With elves and assassins in pursuit, can they find the city and keep it secret so they can plan a counter attack?
The story is great though the author is clear a fan of Star Wars. Emily hires a gruff pilot in a seedy bar where fights break out. The pilot's ship is a bit of a shambles. They are going to a cloud city. A bounty hunter is in pursuit. Even borrowing all these elements, there's plenty of imagination and great characters to make this an exciting read.