Airborn Novel by Kenneth Oppel

Matt Cruse is the 15-year-old cabin boy aboard the Aurora, the 900-foot luxury airship he has called home for the past two years. While crossing the Pacificus, Matt fearlessly rescues the unconscious pilot of a crippled hot air balloon. Before he dies, the balloonist tells him about the fantastic, impossible creatures he has seen flying through the clouds. Matt dismisses the story as the ravings of a dying man, but when Kate de Vries arrives on the Aurora a year later, determined to prove the story is true, Matt finds himself caught up in her quest. Then one night, over the middle of the ocean, deadly air pirates board the Aurora. Far from any hope of rescue, Kate and Matt are flung into adventures beyond all imagining. . .