It's a fictionalised biography of aircraft designer Jiro Horikoshi (whose name I've just had to look up despite watching an entire film about him just over 12 hours ago), from bespectacled, aeroplane-obsessed kid to brilliant aeronautical engineer troubled by the sight of his creations going off to war. As the decades pass, Japan modernises, shown by increasingly crowded waters and speedy trains. We see Jiro's dreamed conversations with Italian designer Caproni, his visions of a graceful, gull-winged monoplane, and his visit to a darkly mechanised Germany, while we know that Japan is heading for the inevitable.
See it if you like anime, see it if you like looking at beautiful Japanese landscapes, but most of all see it if you love aircraft and believe in the film's message: Airplanes aren't for making money, or making war. Airplanes are beautiful dreams.