There is a side mission unlocked after the game called Sky Wolf.
Go in the side entrance of the airport. That's the only Hunter I have
had access to. Although I reached 100% after the final storyline
mission, so I am unclear whether this is a storyline completion
reward, or a 100% completion reward. The Fort Baxter Base
Rhino is now unlocked for me as well, and when wearing the
final "Army Fatigues" outfit, the soldiers no longer shoot at Vic.

So go to the side entrance of the airport, turn right, it should be
up against the fence. You can see it on your way in as well.
That's the only Hunter I've found.

L§

Go to Escobar Intl. Airport and enter via the western entrance (The one
near the Civil Asset Forfieture's boat dock) and you'll find a hunter
just north of the entrance.

It's quite near the Maverick used for "Vice Sights" and triggers the
extra mission "Skywolf".

After "Last Stand" there's a Rhino unlocked at Fort baxter, but I find
the Hunter is far more fun. I was hoping that one would spawn at
Lance's house after 100%, but to no avail.

Cheers,
Rob

"Do sugar cubes have dots or is that a dice I just put in my tea?"

To the world you are somebody, but to somebody you are the world.