Is this a spacecraft, jet fighter, or spacecraft/jet fighter hybrid? If its atmospheric, I think it should have little tiny landing gear bays visible somewhere, or at least rectangular bumps on the bottom where they would be.
After all, if your spacecraft's hovering abilities conk out a mile above a planet surface when trying to land, you'll be NEEDING landing gear...
As for the fuselage itself, i love the idea...maybe two small fins on the back next to the engines, two 45-degree slanted fins on either side of them? We already have jets that look like that...