AeroVironment (AVAV) may be the closest thing to a pure drone firm.

The California company generated $209 million in unmanned aircraft systems revenue last year, making up a whopping 83% of its total sales.

AeroVironment is best known for building the Nano Hummingbird, which can fit in the palm of your hand and was named one of the best inventions of 2011 by Time.

The company makes a small army of light-weight drones, including the Switchblade. This battery-powered drone launches from a tube and unfolds its wings, transforming itself into a weapon that has a small warhead. Investment firm Jefferies estimates Switchblade will bring in more than $40 million of revenue in fiscal 2015.

All told, AeroVironment said it has delivered more than 20,000 new and replacement air vehicles in the U.S. and elsewhere.

Jefferies believes each of AeroVironment's three focal points -- Switchblade, global initatives and the civilian drone market -- offer a market opportunity in the range of $1 billion or more.

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