You'll find the black 'dash marks' of the flag near the 'front' of the 'green energy pool' of the image (where the two ends of the 'wings' meet to form the long, narrow gap at the front end of the ship).
It also turns out it's in the rendering of the in-game model, albeit from a different orientation, if I'm not mistaken.
For a quick comparison, here's the South Korean flag:
If this is old news, sorry that I'm so far behind on it. Still an interesting little tidbit of design.