Running a Vietnam War campaign can require a large number of vehicles and their stats. With this post, I will give some GURPS sources for such a purpose.
The following sources give full Fourth Edition stats:
GURPS Basic Set
M35A1 Cargo Truck, use the TL6 2 1/2-Ton Truck
Kaiser-Willys M38A1 Jeep, use TL6 Jeep
Kaiser-Jeep M715 Truck, use TL7 Pickup Truck
Douglas C-47 Skytrain, use TL6 Twin-Prop Transport
Bell UH-1D Slick, use TL7 Light Helicopter
GURPS High-Tech
Ford M151 MUTT
Hughes OH-6A Cayuse
Uniflite PBR MK 2
GURPS SEALS in Vietnam
Goodrich Inflatable Boat, Small
Boston Whaler STAB
Grafton Boat LSSC
Atlantic Research MSSC
Båtservice Verft PTF Nasty-class
Seward Seacraft PCF MK 1 Swift-class
Higgins HSSC
General Dynamics MK 7 MOD 6 SDV
North American OV-10A Bronco
Bell UH-1B Gunship
Bell PACV
Pyramid #3/53 Action, Dogfight Action!
MIG-21 Fishbed
McDonnell Douglas F-4 Phantom
Unofficial GURPS Fourth Edition sources:
An excellent pdf collection of Vehicles stats can be found here VEHICLE COLLECTION FOR GURPS Fourth Edition. It contains a number of Vietnam-era vehicle stats, civilian and military, Free-World and Communist Bloc:
Volkswagen
Citroen 2CV
Sachsenring Trabant 601
Piaggio Vespa 150
AMC Rambler Six
Mercedes-Benz Unimog 404
Ford Transit Mark 1
GAZ-66B
AEC Routemaster
Neoplan Skyliner
General Motors New Look 5303
John Deere 4020
Antanov An-2
Beechcraft Baron B55
Douglas AD-6 Skyraider
Bell AH-1G Cobra
Boeing CH-47C Chinook
Other blogs
The M113 is thoroughly stated up here.
There are a number of other GURPS sources for vehicle stats, though not specifically Fourth Edition stats. For converting real-world data into Fourth Edition stats, I highly recommend using David Pulver's article Describing Vehicles in Pyramid #3/120 Alternate GURPS V. This article provides an excellent extended discussion on how to create Fourth Edition-style GURPS stats using real-world information. The SR-71 reconnaissance aircraft, of Vietnam-era vintage, is a worked example in the article.
GURPS Special Ops
Sikorsky CH-53
Lockheed C-130 Hercules
Note: the first edition of Special Ops has some additional stats for other Vietnam-era vehicles, both Free-world and Communist Bloc.
GURPS WWII Dogfaces
Essex-class Aircraft Carrier (Note: These WWII-era aircraft carriers were modified and their aircraft complement changed significantly by the time of the Vietnam War, but this presents a starting place, in any event.)
There are a number of blogs that provide unofficial GURPS Third Edition sources. These can be easily converted to Fourth Edition stats using Basic Set and Pulver's Describing Vehicles article.
The GURPS Aerodrome blog provides an enormous amount of GURPS Third Edition stats. Notables include:
Bell AH-1 HueyCobra
Douglas A-4 Skyhawk
Northrop F-5E Tiger
As poster Phaelen Bleux he has posted some notable designs on the SJGames forums:
While this is by no means a complete accounting, as you can see, there is a surprisingly useful number of vehicles statted up for any 1960s or Vietnam War-era campaign. Helicopters, small boats, and some aircraft are well represented.