Its completely modless, just like what @StockPlanesRemastered said, you use the designer suit in the game

The designer suit that's built into the game. You can upload a build with screenshot that have blueprints in the background. So, what I do is instead of blueprints, I put the screenshot where it would go, and sign up the camera so that the plane itself is out of view.

modless
Though, sometimes I use darkblue for high atmosphere or space scenes

shaders