High Quality Content by WIKIPEDIA articles! An optical landing system (OLS) (nicknamed "meatball" or simply, "Ball") is used to give glidepath information to pilots in the terminal phase of landing on an aircraft carrier. From the beginning of aircraft landing on ships in the 1920s to the introduction of OLSs, pilots relied solely on their visual perception of the landing area and the aid of the Landing Signal Officer (LSO in the US Navy, or "batsman" in the Commonwealth navies). LSOs used colored flags, cloth paddles and lighted wands.