With the help of my friend, i debuged ACAH files (PC version) and found these. Im pretty sure they are ACAH's concept arts because you can compare my pictures with this image from Project Nagase website (Which is Project ACES's ACAH development blog):
Here're some of them
Turned out Markov and Ilich original flew the Berkut and Su-33 instead of PAK-FA in the final game though.
Download link for anyone interested:
Edited by FoxHoundElite, 04 November 2016 - 10:21 PM.