The last assignment for Armstrong in the Gemini program was as the back-up Command Pilot for Gemini 11, announced two days after the landing of Gemini 8. Having trained for two flights, Armstrong was quite knowledgeable about the systems and was more in a teaching role[53] for the rookie backup Pilot, William Anders. The launch was on September 12, 1966,[54] with Pete Conrad and Dick Gordon on board, who successfully completed the mission objectives, while Armstrong served as CAPCOM.
Following the flight, President Lyndon B. Johnson asked Armstrong and his wife to take part in a 24-day goodwill tour of South America.[55] Also on the tour, which took in 11 countries and 14 major cities, were Dick Gordon, George Low, their wives, and other government officials. In Paraguay, Armstrong impressed dignitaries by greeting them in their local language, Guarani;[56] in Brazil he talked about the exploits of the Brazilian-born Alberto Santos-Dumont, who was regarded as having beaten the Wright brothers with the first flying machine with his 14-bis.[57]