I think it should be flying the Jolly Roger!
Some of the Idea books, circa the 1980s, had photos of Castle and Space System elements combined in really odd ways. For example, a castle with antenna and radar dishes, a moon baseplate next to a green baseplate, a lunar tower flying medieval flags, or a knight riding through a Classic Space scene. Your ship has a long and proud tradition (although I think it looks much nicer than the Idea book designs)!
Here is an example, with apologies for the big photo. It comes direct from Peeron.