“We have all heard the saying "the man with a plan is king." I believe a man without a plan is just a pawn to circumstance and embarking on a losing strategy.”

Che sarebbe pensier non troppo accorto,
Perder duo vivi per salvar un morto.
Canto XVIII, stanza 189 (tr. B. Reynolds)
Orlando Furioso (1532)

Source: Seeing Redd

The earliest appearance yet located of this statement is in 50 Ways to Lose Ten Pounds (1995) by Joan Horbiak, p. 95, where it is quoted as an anonymous proverb. It seems to have circulated as such for a few years before it began to be attributed to Saint Exupéry around 2007.
Disputed

Radio address http://georgewbush-whitehouse.archives.gov/news/releases/2007/01/20070113-2.html discussing his plan to send 21,500 more troops to Iraq (January 13, 2007)
2000s, 2007

The Pageant of Life (1964), On Planning for a Better World

From a speech to the National Defense Executive Reserve Conference in Washington, D.C. (November 14, 1957) ; in Public Papers of the Presidents of the United States, Dwight D. Eisenhower, 1957, National Archives and Records Service, Government Printing Office, p. 818 :
1950s
Context: I tell this story to illustrate the truth of the statement I heard long ago in the Army: Plans are worthless, but planning is everything. There is a very great distinction because when you are planning for an emergency you must start with this one thing: the very definition of "emergency" is that it is unexpected, therefore it is not going to happen the way you are planning.

Source: Someone Like You (1998)

On his presidential plans New York Times (14 September 1986)

Response to the question: "You’ve been teaching about, researching, and consulting on business and corporate strategy for 35 years. What changes have you seen in that time?"
"McKinsey Quarterly interview," 2007