Who in UK Forces in World War 1 wore an RAF blue uniform?

In World War I, personnel in the Royal Air Force (RAF), which was established in April 1918, wore the distinctive RAF blue uniform. This included aviators, ground crew, and support staff associated with the air service. Prior to the formation of the RAF, members of the Royal Flying Corps (RFC) also wore military uniforms that were often in similar shades, but the official RAF blue became the standard once the RAF was created.