Calgary-based CDL Systems may be the most important defense contractor you never heard of. But Lockheed Martin (LMT 1.47%) 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 (BA -0.56%) to Textron (TXT 0.57%), and from AeroVironment (AVAV 2.09%) to Northrop Grumman (NOC 2.58%).

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