Exactly what the title says.

639357 Not trying to toot my own horn, but I made one if you want to check that out.

639375 Ok, thanks

I have a few personal favorites if military ponies is what you seek.

1. Falling Stars By Rokas.
This is a sci-fi military story, which involves humans and is a cross-over from the Battletech universe. But even if you've never heard of Battletech before, don't worry. You don't need to know anything about it to enjoy this story. I didn't going in, and I still don't, but this guy does such an awesome job with giving you everything you need as you go along that it doesn't matter. He's also really close to being done with it as well, so there is no reason not to dive into this awesome story.

2. Hired Gun By Gyvon.
What happens when a snarky private military contractor from Texas gets hired for a job that sends him to Equestria? Excellent question. I bet he's wondering the same thing. This is just a funny story. Only drawback is it's a good ways off from being done.

3. Equestria: Fires of Liberation By smoers06
This guy does and excellent job with military action, and finds a very creative way to integrate humans into the mix. If you've ever played the Ace Combat series of video games, you'll recognize a few cameos, but if not, don't worry. Again, the only fandom you need to be a part of to understand this story is ours. But be warned; it hasn't been updated in a very long time.

Hope these get you off to good start here. There's more out there, and like I said, these are just a few of my personal favorites. A good way to find more stories is to browse through the multitude of groups on the site, and just pick a few fics that look interesting. You might not like every one you find, but there's an occasional diamond in the rough that makes the search worth it.

639357 Hornethead wrote a fantastic one, Displacement: a US Navy SEAL is transported to Equestria and starts a new life in Equestria while Fighting his PTSD, its one of the better fics I've read. and then he wrote a sequel to it as well.

*Caugh caugh self promotion caugh.*

About the Flight 19 fiasco, and how the USAF gets stuck in the bermuda triangle Equestria.