The WLA is a motorcycle that was produced to US Army specifications in the years during and around World War II. It was based on an existing civilian model, the WLD, and is of the 45 solo type, so called due to its 45 cubic inch engine and single-rider design. The same engine, in a slightly lower state of tune, also powered the three-wheeled Servi-Car (the "G" family), leading to the "solo" distinction.

The US Army would use motorcycles for police and escort work, courier duties, and some scouting, as well as limited use to transport radio and radio suppression equipment. Allied motorcycles were rarely used as combat vehicles or for troop mobility, and so were rarely equipped with sidecars as was common on the German side. Nevertheless, the WLA acquired the nickname "Liberator", since it was seen ridden by soldiers liberating occupied Europe.