BD Armory is a popular KSP mod that adds guns and missiles so you can recreate warplanes within the physics of KSP. Even Better, the mod has support for AI pilots which means you can load up a bunch of planes and set them against each other. http://forum.kerbalspaceprogram.com/threads/85209-1-0-BDArmory-v0-8-3-(critical-fixes-improved-AI)-Dev-Thread-May-30 Also we looked at Voidrunner: https://www.kickstarter.com/projects/1339028258/voidrunner And finished with Outer Wilds: https://www.fig.co/campaigns/outer-wilds