Calgary-based CDL Systems may be the most important defense contractor you never heard of. But Lockheed Martin (NYSE:LMT) sure knows CDL. In fact, as of a few days ago, Lockheed owns CDL -- and with it, Lockheed bought itself a key piece of the infrastructure that controls unmanned aerial vehicles flown by everyone from Boeing (NYSE:BA) to Textron (NYSE:TXT), and from AeroVironment (NASDAQ:AVAV) to Northrop Grumman (NYSE:NOC).

Why was Lockheed's CDL purchase such a smart buy? Listen in, as Fool contributor Rich Smith explains.