Matt is a 15-year-old cabin boy working aboard the luxury airship Aurora. He took the job three years prior following his father's death, sending his wages back home to support his mother and sisters. Deeply connected to the air and the ship itself, Matt is highly practical, observant, and skilled in aeronautics. His working-class background prevents him from attending the formal Air Academy, driving his intense desire to earn a promotion through hard work.

Kate is a wealthy 15-year-old first-class passenger traveling on the Aurora. She possesses a fierce scientific curiosity and seeks to validate her late grandfather's sightings of unidentified flying creatures. She frequently ignores societal rules and class boundaries to achieve her goals. Her intense focus on discovery causes her to overlook the professional risks her requests force onto others.

Captain Walken commands the luxury airship Aurora with calm authority and fairness. He respects hard work and skill over social class, recognizing Matt's dedication to the ship. He leads his crew through disasters with practical, steady guidance and prioritizes the safety of his passengers above all else.

Szpirglas is a notorious air pirate who leads a crew targeting luxury vessels. He affects a courteous, gentlemanly demeanor that masks his extreme brutality and willingness to use lethal force. He is a highly capable airman who leverages his skills for greed, serving as a dark reflection of what a skilled aviator can become.

Bruce is the son of the Aurora's wealthy owner who joins the crew as the new junior sailmaker, taking the promotion Matt hoped to earn. Despite securing his position through nepotism, Bruce is a friendly, well-meaning young man who readily acknowledges his lack of practical experience. He faces immense pressure from his father to eventually take over the family business.

Benjamin is an ailing balloonist attempting a solo flight around the world. He is Kate's grandfather and a passionate explorer. His final, feverish claims about beautiful creatures in the sky set Kate on her scientific quest.

Miss Simpkins is Kate's strict and highly critical chaperone. She actively disapproves of Kate's scientific interests and attempts to aggressively enforce class boundaries between Kate and the working crew.

Baz is an 18-year-old crew member and Matt's supportive roommate. He provides practical friendship and often commiserates with Matt over the demanding behavior of first-class passengers. He is eagerly looking forward to returning home to propose to his sweetheart.

Crumlin is Vikram Szpirglas's ruthless first mate. He follows orders without hesitation and enthusiastically hunts exotic wildlife for sport, showing zero regard for the lives of others.

Doc Halliday is the physician assigned to the Aurora. He attends to injured passengers and crew members, offering calm medical counsel during shipboard emergencies.

Theodore is Vikram Szpirglas's four-year-old son. He lives in a concealed settlement and admires his father, viewing him purely through the lens of paternal affection and adventure stories.

Mr. Featherstone is the chief wireless officer on the Aurora. He manages radio communications and takes immense personal risks to try and secure help for the ship when hostile forces arrive.

Vlad is the cheerful chef aboard the Aurora. He maintains an optimistic attitude during crises and coordinates with the crew during covert operations, using his position in the kitchen to assist his friends.

Mr. Levy is the chief sailmaker on the Aurora. He directs the difficult physical labor of patching the ship's massive fabric exterior following pirate attacks and storm damage.

Rhino Hand is a burly member of Vikram Szpirglas's pirate crew. He participates in the violent takeover of the airship and guards the engine areas during the occupation.

The cloud cat is an unidentified, winged predator that lives almost entirely in the air. Resembling a cross between a panther and a bat, the discovery of a flightless, injured cloud cat drives Kate's scientific ambitions and brings the characters into close contact with the dangerous species.

Matt's father is a former sailmaker who died in a tragic fall from the Aurora. His memory heavily influences Matt's deep connection to the sky, his career path, and his profound, lingering grief.

Matt's surviving parent. She relies heavily on the wages Matt earns aboard the Aurora to keep the family financially stable after the death of her husband.

Matt's young siblings back in Lionsgate City. They represent Matt's heavy domestic responsibilities and form his primary motivation to seek higher wages.

Teresa is Baz's sweetheart waiting for him in Sydney. She represents the stable, adult domestic life that the older crew members aspire to reach once their flying days are over.