So, I finally collected all skins for Ace Combat 7, some of them have been a tedious grind. Info and requirements below:

F104C (Italian AF) Complete Campaign using MG only
A10C Destroy 200 aircraft with MG in campaign mode
F14D (US NSAWC) Complete all missions on Normal difficulty with an SRank
F22 (Fictional) Complete all missions on Hard difficulty with an SRank
YF23 ("Black Widow" prototype) Finish first in the Battle Royal multiplayer mode three times
Rafale M (French Marine) Win 50 Team Deathmatches
Mig31B (Fictional) Sortie 100 times in multiplayer
Su30SM (Real life Su30MK skin thanks to toarahi for pointing that one out) Complete campaign without taking damage
Su37 (Fictional, based on Russian Su27 skin) Complete Mission #19 WITHOUT using the MG at all
X02S (Fictional... derp) Complete campaign in under 4 hours

Most of the skins are tied to singleplayer mission medals.

Check out my Instagram and be the first to see new WIPs:   / skyline_i.g  

Graphic mod used: https://www.gta5mods.com/misc/natura...

Download page at gta5mods.com:
https://www.gta5mods.com/users/Skyli...

My specs:

CPU: Intel(R) Core(TM) i52500K CPU (overclocked to 4GHz)
GPU: Nvidia GeForce GTX 1070 (Palit Gamerock)
RAM: 16GB
OS: Win 10 64bit
1TB HDD and 500GB SSD

Games actively modded:
GTA V
GTA IV (including EFLC)
GTA SA
HAWX
FSX