All principal characters—including Jiro Horikoshi (voiced by Hideaki Anno), his love interest Nahoko Satomi (Miori Takimoto), colleague Honjo (Hidetoshi Nishijima), and supporting figures—are portrayed by Japanese voice actors in roles that match the real historical context of pre-WWII Japan. This approach avoids any modern recasting or demographic adjustments, keeping the focus squarely on the story’s original cultural and temporal framework. The film’s core premise revolves around personal dreams, romance, and engineering ethics rather than any contemporary activist framing.

Jiro’s lifelong pursuit of beautiful aircraft, his romance with the tuberculosis-stricken Nahoko, the 1923 Kanto earthquake, and the personal costs of wartime engineering are presented through recurring dreams of Italian designer Caproni. Miyazaki has explicitly described his intent as capturing the pursuit of beauty amid hardship and offering pacifist reflections on the era, without injecting modern social justice themes into the narrative.