The SD-103 type was a class of shuttlecraft used by Starfleet in the 23rd and 24th centuries. This shuttle type was known to be used for orbital personnel transport. (Star Trek VI: The Undiscovered Country; Star Trek Generations)
Shuttles of this type
During the interim between the Star Trek VI: Undiscovered Country and Star Trek Generations, the studio model was altered to appear as the Sydney-class in TNG: "Relics" and DS9: "Playing God", et al. For further information on the studio model, see: SD-103 model.
The Star Trek Encyclopedia (4th ed., vol. 2, p. 349) stated that SD-103 types were in fact Sydney-class ships, built without warp drive for use as large shuttles.
The SD-103 type shuttle parked on the Enterprise-D's saucer in Generations was not an actual studio model, but rather part of the matte painting into which live action photography was later inserted in post-production. (Cinefex, 61, page 77) The USS Farragut in-flight shuttlecraft was stock footage from Star Trek VI, flopped and edited in post-production as the actual studio model had already been converted into the Sydney-class.
The USS Melbourne was equipped with two SD-103 type executive shuttles. These shuttles were 'parked' in the cargo bay of the secondary hull. Though not seen in the episode, they can be seen in a photo, which was put on Instagram along with other photos of the Excelsior-class studio model.