(Cross-country plane trips have one thing going for them: the opportunity to read long books in one sitting.)
In War and Peace, Tolstoy discusses at length both the sheer messiness of war and the real problems involved in representing it. Powell takes a slightly different tack, for there is remarkably little "war" in A Dance to the Music of Time's Third Movement--if, by "war," you mean fields of battle, high heroic deeds, international political intrigue and so forth. Indeed, if you handed this novel to a group of under-instructed undergraduates, they would most likely not understand why anyone was fighting or to what end. Moreover, every death occurs offstage, even though the toll includes several previously important characters. Instead, Jenkins traces wartime bureaucracy, much of it amazingly petty: haggling over positions, misguided obsessions, minor cultural clashes. At the same time, some of the bureaucratic red tape turns out to have real consequences; most notably, Widmerpool's machinations indirectly cause at least two deaths.
Powell's strategy here certainly carries on his overall plot's emphasis on the problems of finding a pattern: Jenkins, a participant in WWII, does not see "the war" so much as he finds it violently disrupting his own life's networks. But I think that Powell also sets out to upset our notion of what constitutes a wartime plot. On the one hand, he alludes repeatedly to the boy's adventure stories found in the Boy's Own Paper, with their plucky heroes and triumphant progresses; on the other, he makes one of his characters obsessed with the centurion from Kipling's Puck of Pook's Hill. The stories for boys not only make war seem like good fun, but also have clear-cut plots, designed to inspire their readers to patriotic emulation. Kipling's centurion is a slightly more complex case. Puck of Pook's Hill offers a mythical "living history" of sorts: via the agency of Puck, two young children hear figures from the past narrate their own deeds. The centurion, whose experiences stretch over three stories, has been sent by Maximus to help command the guard at Hadrian's Wall. But his position is something of a punishment as well, for putting a disinterested devotion to justice over his career prospects. Even so, both the centurion and his friend go on to devote themselves wholly to Maximus' interests, in the end refusing to serve under Theodosius after Maximus loses his head (literally). The Roman soldiers thus represent an oasis of pure duty and moral obligation in a sandy desert of Roman decay. In Powell's novels, they also represent a wholly unattainable ideal within the bureaucracy that makes up modern warfare; after all, the centurion-obsessed officer, Jenkins' superior, winds up losing his command and eventually leaves the army altogether. At the same time, though, both this ideal and another proposed by Vigny--the soldier as "monastic" devotee to his calling, working steadily through boredom as well as excitement--offer possibilities for thinking about the self in wartime, possibilities which stand in stark opposition to Widmerpool's relentless desire for self-advancement. Jenkins, however, never conceptualizes himself in either fashion.
(Incidentally, here's a quite nice high school essay--from an Andover DTTMOT website--on how soldiers who yearn for the monastic ideal eventually self-destruct. The site also reprints one of the poems associated with the Roman centurion, which Jenkins quotes repeatedly and usually with some irony.)