He returned to Eastern Air Lines after the war, becoming a senior pilot with the airline. In 1948, at off the Florida coast, Merrill's calm and skillful management of an in-flight emergency was evident when a propeller on an EAL Constellation tore through the fuselage and killed a steward instantly. Merrill was credited with saving the lives of 69 people on board. In 1953, he piloted an Eastern Airlines Super Constellation in an aviation promotional movie called "Flying with Arthur Godfrey", with Godfrey as narrator. He would officially retire from Eastern Air Lines on October 3, 1961 after flying a Douglas DC-8 from New York to Miami. At retirement, he reputedly had flown the longest cumulative distance of any pilot in commercial aviation history, and ranked as the second most senior pilot with the airline after 36,650 hours flown over a period of 33 years.