Drones become big business

The U.S. military is increasingly using unmanned aircraft systems like these in its operations.

That means big money for the companies that make them.

Companies benefiting from this spending include Northrop Grumman (NOC), General Atomics, Lockheed Martin (LMT), Boeing (BA), Israel Aerospace, and Textron (TXT). All numbers in this story, except those for the F-35, were provided by IHS Jane's Principal Analyst Derrick Maple.

It's estimated that drones make up 31% of the U.S. military's aircraft fleet, although many of those aircraft are small and unarmed.

A drone is far cheaper than a fighter plane, but the two are suited for totally different missions.

The drone can hover for long periods of time and can operate in places too dangerous to send a person. It's generally used in places where the risk of it being shot at is low, or on reconnaissance missions where it's not critical that the drone survives.

A fighter plane is generally much faster, much more maneuverable, and can carry more weapons, said Dan Goure, an analyst at the Lexington Institute. A fighter plane, or cruise missile, is used when it's imperative to take out a well-defended target.