Our speaker is looking out his airplane window as they're flying somewhere over Kansas, feeling distant from both the earth and his own emotions. He's a little bored, and remembers being captivated as a kid, looking up at the airplanes crossing the sky.
But flying has lost its magic for him now, so he turns to the book he's reading (Moby-Dick). He considers his life, and the idea of growing old and dying in a corridor like that of an airplane. It would be much better, he decides, to be out on the whaling boat, like the characters in his book—to feel that sense of adventure, that connection to the elements, and that uncertainty of where they're headed next.