The Hagerstown Aviation Museum recently acquired a bunch of GSE according to the
February 2018 edition of their Pegasus Flyer newsletter. It includes:
- Unknown Yellow Tug – Donated by the GSA and came from Letterkenny Army Depot.
- 1952 Clark Tug – It was last used by US Air Express and was found at the Marion Auction.
- Towmotor Forklift – It was used at Fairchild in the 1950s and 60s and was purchased at the Hagerstown Aircraft Services auction a few years ago.
- 1946 Mack 750 Fire Truck – It was originally built for the US Army and was found at the Michaux State Forest in Fayetteville, Pennsylvania. It was donated by the GSA through the Maryland Surplus
office and arrived at the museum on 3 February 2017. - 1957 Walter ARFF Crash Truck – This truck was purchased by Fairchild in 1957 and used as part of their fire department until 1984. It was donated by Tony Cook of Triadelphia, West Virginia and arrived at the museum on 1 December 2017.
A crane at the Connecticut Air & Space Center was covered in a
previous post, but they also have a blue and white tug that is not listed on their website:

(Source:
Google Plus)
The Fagen Fighters WWII Museum has a small yellow tug:
Link to Oversize Picture(Source:
Warbirds News)
Ginge Copenhagen firetruck at the Finnish Aviation Museum in Helsinki, license plate number EJK-52, marked as number 5, used by the Finnish Civil Aviation Authority:

(Source:
Flickr)
They also have a searchlight:

(Source:
Flickr)
I don't know what this thing is and whether it is technically GSE, but it is at the Karjalan Aviation Museum:

(Source:
Google Plus)
Another possible GSE vehicle at the Karjalan Aviation Museum:

(Source:
Google Plus)
The Italian Air Force Museum has what appear to be two olive drab ground power units in their Skema Hangar:

(Source:
Ministero Della Difesa)
One can be seen in the background of this picture:

(Source:
Flickr)
The Newark Air Museum has a Houchin Mk.5 Ground Power Unit:

(Source:
Flickr)
The National Museum of Flight Scotland has a Stonfield firetruck, marked as Highlands & Islands Airports license plate CYT 673V:

(Source:
Flickr)
The Brooklands Museum was the subject of an
earlier post, but apparently there is more GSE that is not included on their website:
Morris Minor 6cwt Van, marked as British Caledonian Airways, license plate YYC 708H

(Source:
Flickr)
A Morris Minor Quarter Ton Pickup Truck, marked as Dan-Air London, license plate UDD 815

(Source:
Flickr)
The Ansett Museum in Australia has a white tug:

(Source:
Flickr)
Not to be confused with the
darker blue tug at the C. R. Smith museum, the Delta Flight Museum has a blue tug:

(Source:
Flickr)
While not a museum, the Olympia Regional Airport has 3 aircraft tugs named Larry, Curly, and Moe:

(Source:
Flickr)
I have to admit, I am enjoying all the comically named tugs in recent posts!
Finally, I'd like to give a shout out to the
"Airport Vehicles" Flickr group. I found a good number of the photographs in this post by searching the group for "museum".