Shares of AeroVironment (AVAV +4.46%) soared more than 20% this week, to around $171, after the drone and defense specialist reported its fiscal fourth-quarter results. The quarter was a blowout by almost any measure -- record revenue, adjusted profits that more than doubled, and a funded backlog that swelled past $1 billion.Is this the start of a multiyear up cycle in military drones and the systems built to stop them, or a one-quarter spike that borrows from future demand and leaves a harder comparison be ...