There is a reason it isn’t called Flymen. Flyboys, which follows James Franco as an American volunteer who pilots a fighter plane for the French in World War I, is thoroughly adolescent. That’s fine during the exciting – albeit computer-assisted – dogfight scenes, but not so good for the rest of the film. Here it’s the gee-whiz dialogue, not the hissing bullets, that makes you cringe. It all floats by as breezily as one of the planes in the air, yet there’s something unsettling about a war movie of so little consequence.