It's not easy being South Korea. With two aggressive and not-so-friendly neighbors living nearby, the democratic nation is feeling antsy, and looking to buy a few good fighter jets to help ease its nerves.

Both Boeing (BA -0.08%) and Lockheed Martin (LMT 1.59%) are competing to sell Korea the planes it needs. Both Boeing stock and Lockheed Martin stock could benefit from the billions of dollars Korea wants to spend to beef up its defense.

And they're not the only ones. Motley Fool contributor Rich Smith explains...