Hmmm, brings up an interesting question.
I have been quietly surfing the net for inspiration, reference pics, and even models to examine and build from scratch using the knowledge gained by examining others work. I have over 100 spaceship models all skinned by my own hand using my own Photoshop textures.

None of my spaceship models contain geometry from the originals, all are significantly less polygon intensive than any that I examined, and none are outright duplicates (most don't even resemble the original, really) of the originals.

Most spaceships that I have seen tend to take an influence from Star Trek, Babylon, BattleStar Galactica, or other popular shows. Star Trek, Enterprise, etc are not part of the description for the models, so just how much of a shape or look would be considered Trademark infringement?

Cheers!
Mark