Hi Kolja, So it was all airbrushing and carefully cut masking tape. I'm lately using a tape that is stronger than usual modelling masking tape. It requires a little bit more patience to remove it to avoid paint clipping but gives sharper edges.
Wow. How did you do the red-white-red stripes on the wing and the other decorations so cleanly? Did you use masking tape or "just" very clean freehand? I am alwways struggling to get these kinds of things to look sharp.