Symbolism, Imagery, Allegory
The Bad Year Blimp
This giant blimp is one of the first powerful images we see in the novel. In the very first chapter, we follow the Zeppelin as it flies over France, Switzerland, Germany, Tokyo, and the United States.
It makes quite an impression on young Louie, and he finds it's "fearfully beautiful" (1.1.8). One of the things he doesn't realize at the time though, is how much the blimp is like the peace the world is living in at the time: it isn't meant to last. The blimp was retired in 1937. Before it did, though, it heralded Hitler's arrival on more than one occasion—and nothing says goodbye peace like hello, Hitler.
In short, the graf zeppelin is a symbol of what's to come—an era of terrible, and terribly destructive, war.