Silver City Air Ferry 'City of Salisbury'
This picture shows a car being driven aboard the Silver City Air Ferry called 'City of Salisbury'.
I think the airplane may be a Bristol 170, but I don't know the location although this page suggests it could be either Lydd or Lympne airport. Irrespective of the location, the image is quite interesting because you don't generally see people transporting their car on an aeroplane these days.
This photo was added to the collection on March 12, 2018
For what it's worth, the car being loaded is, I believe, a 50's model Rover. Does the registration plate number give any indication of the era?
As you say, it's most unusual to see a car being driven onto an aeroplane.