Most of the factions in Battle Aces came together relatively organically over the course of the project, except for North Performance. We needed a whole set of new units to unlock on your first playthrough, and they needed to be catchy designs that could be technologically surpassed as you then went on to unlock more units over time.
I settled on a pretty retro look, and characterful faces for more of the units compared to some of the more serious military bots elsewhere in the game.
Airship and Hunter models by Chadwick Dusenberry
https://www.artstation.com/chadwed
Butterfly and Ballista models by Nic Reid
https://www.artstation.com/nicname48/albums/12982160