The Elven Swan Ship immediately brings to mind the much larger Halfling Swan Ship, so connecting the two makes for great Spelljammer lore.
Name: Swan Shuttle
Built By: Elves, halflings
Used Primarily By: Halflings
Cost: 500 gp
Tonnage: 1 ton
Hull Points: 1
Maneuverability Class: B
Landing—Land: Yes (Special)
Armor Rating: 10
Saves As: Thin wood
Power Type: Non-magical; major or minor helm
Ship’s Rating: 2 (Non-magical) or as per helmsman
Cargo Capacity: None (personal items or up to six individuals)
Keel Length: 15′
Beam Width: 35′ (wingspan)
Description: The Swan Shuttle is an early precursor to the Elven Flitter designed to look like a swan. Built rather than grown, it is a simple craft designed to quickly move a small group of individuals from one ship to another, although in a pinch it can ferry a spell caster into range of an enemy vessel. The extended wings are mobile, granting the small craft its maneuverability. A maximum of six creatures (small or man-sized) can sit on the benches lining the small hull, with no cargo space besides small personal items (packs, weapons, etc.), and the ship cannot be outfitted with weapons of any sort. Most Swan Shuttles are built with a pair of wooden runners on the underside of the hull, allowing landing on water or land; without the runners, this vessel can only touch down on water.
With the development of the grown Flitters, the Swan Shuttle became obsolete. Most of the remaining ships, as well as the plans for building them, were given to allied halflings, who loved the design and appearance so much it became the inspiration for the much larger Swan Ship (which, in turn, is often purchased by elves). Most Swan Ships will have at least one dismantled Swan Shuttle on board, although it can be re-assembled in just a few rounds by four halflings.
One thing to note is that the Flitter really should be Maneuverability Class A. As it stands now, the Flitter is less maneuverable than many larger ships (such as the Goblin Blade), despite elven ships being known for their maneuverability. That would also serve to make the Swan Shuttle clearly inferior to the Flitter.