Sommerfeld Tracking, named after German expatriate engineer, Kurt Joachim Sommerfeld, then living in England, was a lightweight wire mesh type of prefabricated airfield surface. First put into use by the British in 1941, it was a wire netting stiffened laterally by steel rods. This gave it load-carrying capacity while staying flexible enough to be rolled up. Sommerfeld Track was used extensively by the Royal Air Force in the Second World War to make runways at their airfields, as it could be deployed quickly.