british softskins

Queen Mary trailer
A Queen Mary trailer is a type of semi-trailer combination designed for the carriage and recovery of aircraft. The trailer was made by Tasker Trailers of Andover with Bedford or Crossley Motors tractors.
It was used by the Royal Air Force and Royal Navy Fleet Air Arm during and after World War II.
Key features included:

• Very low floor and ground clearance, typically around 12 inches (305 mm).
• Single axle.
• Wheels outboard of load area.
• Side rails to allow carriage of wings upright, resting on their leading edges.

Load was 5 tons "distributed evenly".
These features were a natural result of the intended load, aircraft being typically light but long. The name is presumed to derive from its length, a reference to the RMS Queen Mary of the Cunard Line.

https://en.wikipedia.org/wiki/Queen_Mary_trailer

Here is one loaded

Here is another one