The stepping up of air strikes in Syria following the attacks in Paris this month has alerted investors to the prospect of increased spending on defence, putting European firms in the sector back on their radar screens. Defence-related stocks have outperformed the market since the Nov. 13 attacks but investors and analysts say there could be further gains to come, not only for prime contractors like BAE Systems and Finmeccanica but also smaller companies further down the supply chain. [...]