Dream sequences are a big part of the film. Jiro is constantly dreaming along with Italian aircraft designer Caproni, who helps him find inspiration for the Zero. When he isn't dreaming with Caproni, he's always visualizing the planes that he's built or the ones he wants to build. It's quite good.
The animation is amazing. There isn't as much footage of the planes in action as I would have liked to have seen, but the movie more than makes up for that in the way the rest of the film is done. Visually, it's a complete masterpiece.
Along the way, there's a 15-minute sequence or so about the hell that cones after an earthquake. The scenes are very down to earth, and there isn't much of Miyazaki's trademark fantasylands. However, it's interesting to see how he tackles more realistic situations.
It's got laughs and it has feels. Really, it's just everything you need for an excellent Miyazaki movie.