Lyndon Johnson actually said...
Mister President, our distinguished Secretary of State, the majority leader of the United States Senate, the minority leader of the United States Senate, leaders of our House of Representatives, join me on this occasion in thanking you for this very cordial welcome and in saying to you: Muchas gracias, Senor Presidente; muchas gracias a todo Mexico!
Context
Remarks Upon Arrival at the International Airport in Mexico City
04/13/1966