I use my Mac for every aspect of a project, from a digital napkin for early sketches, to a high end rendering workstation for photo realistic final imagery, and everything in between. The next phase is to create a clean design sheet from which I can build a 3D model. I typically use Macromedia FreeHand on the Power Macintosh for this step. I find that FreeHand is the best program to create spline based object oriented designs. I find FreeHand much more flexible than Illustrator for creative design.
Illustrator is aimed more at inking scanned sketches rather than designing from scratch.
I designed the ship to lift off vertically. When landed, the control room is lifted high into the air on the tilted neck. A telescoping access tube with a ladder connects the upper passageway with the rear rooms in the belly which remains horizontal. Once aloft the bottom data sail pivots backward and the belly area rotates up flush with the neck. The outer airlock then becomes the bulkhead between the control room passageway and the rear rooms.