Spectacularly good manga with a simple idea at first glance: "Wouldn't racing against dragons by piloting planes be pretty awesome ?" That has a lot more going on under the surface exploring themes of "man vs nature", "man vs man" and "man vs self" with some solid characters and relationships in a world that is "if WW1 Germany was a fairy tale"

The story is 4 volumes and it has a proper ending.

There are only two reasons why this isn't a 10:
1. It has a few flashback chapters that are not particularly good. They aren't terrible either but they bring very little new information, mostly just confirming things that were hinted at in advance.
2. While the art is usually exceptional there are a few chapters where the backgrounds look very messy. It still looks better than most mangas but because it sets such a high standard for itself it's a lot more obvious in the few chapters where they rush the backgrounds.