These are the books by Kenneth Oppel that are reviewed on this site:
Adventures in the Underworld. Superhero bats, unlikely hero bats, deadly enemy bats. Fluffy beasties, human emotions.
Airships, hot-air balloons, pirates, desert islands, cloud cats, adventure and romance...
The race is on to salvage the ghost ship Hyperion sailing at a dangerously high altitude...Matt Cruse and Kate de Vries back in action.