From earlier editions of Traveller, there are a couple of examples of vehicles in various publications.
I'm linking the original images by Rob Caswell on Deviantart (as he's the author).
From Grand Census comes this IIS 4-Man Air/Raft (Grand Census is (c) 1987 Digest Group Publication, original on p.19, one of the many items under "Landing Party Equipment" for Scouts)
Dimensions (according to the book): 4.5m long x 3m wide x 2m high. 27 kiloliter. 1 dTon = 13.5 kiloliter, so it should fit in the "usual" 4 dTon space reserved for an air/raft.
CT didn't come with a proper design sequence for vehicles (there was Striker). MT did have one.
MegaTraveller also had a book called "101 Vehicles", with (indeed) 101 vehicle designs, also by DGP (c) 1988.
There's a variety of air\rafts in the book.
This image collects most (all?) of them: https://www.deviantart.com/robcaswell/art/Traveller-Air-Rafts-399407657
Interesting to note that the one most similar to a "standard" air/raft (4-man open top) only comes to 0.75 dTon.
The "Civilian Sedan" (TL 15 hegira enclosed air/raft) is 4 dTon.
In my current campaign, the Travellers have replaced the "standard" air/raft with the TL 11 Aurum Seeker "buggy", which is meant to serve as a belter's grav vehicle.
I've specced it as follows for Mongoose Traveller:
Skill Flyer (grav)
Speed (Cruise) Fast (High)
Range (Cruise) 3000 (4500)
Shipping 4 Tons
Cost Cr 468,150
Equipment and Weapons
Control Systems (enhanced), Autopilot (advanced), Communications System (improved, 5000km range), Computer/2, Navigation System (improved), Sensor System (improved, 50km range), Vacuum Protection, Life Support (long term), Wet bar, Waldoes (manipulator arms, TL11, Str 15 Dex 12)