Mariner Class said:
The Bird of Prey was suspended on strings for it's frontal assault shot, but it was stationary. From the looks of the setup, they planned to move the camera towards the model. I think what they ended up doing was just moving a single frame of the ship instead.
The Shuttlecraft was also on strings, but I'm pretty sure it was filmed as a single frame.
Well, they were wires, not strings. At the time, flying ships on wires was still an accepted technique, known as the Lydecker method, after Howard and Theodore Lydecker, who developed it for '40s adventure serials (it's how Commando Cody flew) and were using it at the time in shows like Voyage to the Bottom of the Sea and Lost in Space. The Lydecker method could actually produce some pretty nifty action shots, like the classic LiS scenes of the Jupiter 2 soaring through the mountains and crashlanding.
In the case of the Bird of Prey and the shuttlecraft, they were stationary and hanging from vertical wires rather than sliding along horizontal wires, but I'm sure it wasn't due to cheapness or lack of capability. In the case of the BoP shots, it was seen largely from below so that you could see the bird of prey painted on its belly. Suspending it from wires therefore made sense, particularly given that it wasn't a very large model. As for the shuttlecraft, again, it was a small model and wires probably made sense as a means of support, especially given the need for shots of it flying out of the shuttlebay and rocking from atmospheric turbulence. (That big opening in the shuttlebay ceiling just above the turntable was clearly intended to let wires pass through for "puppeteering" the shuttle.)