Calgary-based CDL Systems may be the most important defense contractor you never heard of. But Lockheed Martin (LMT 0.74%) 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 0.96%) to Textron (TXT 1.60%), and from AeroVironment (AVAV 2.31%) to Northrop Grumman (NOC 0.26%).

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