I was able to get the attack helicopter earlier in the game. And now, I have all the missions completed and now I am unable to go get it! Why!?
The Hunter is an Apache helicopter replica. It has duel missles (Circle button) and an auto-aiming machine gun (R1) which locks onto the nearest person/vehicle. It is unlocked once you get 100 out of 100 hidden packages, or beat the final main story mission "Keep your friends close...". It will spawn (show up) at Fort Baxter, near Escobar International Airport. Once you get 100 out of 100 hidden packages, and beat "Keep your friends close...", the Hunter will appear at Fort Baxter and at the southernmost house on the first island. The one with the helipad beside it. You get to see the Hunter first hand in the mission "All hands on deck!" for Cononel Cortez. Hope this helps