Anyone following this thread would profit by reading the entire WIKI entry.

It is sad that this incident has been used as evidence of President Carter's supposed loopiness. His own remarks (and I didn't know he was an amateur astronomer) indicate a properly scientific attitude to his own sighting. Another thing to keep in mind, as a former Naval officer, Carter would have been trained in the rudiments of aircraft observation and identification.

On January 6, 1969 the sky was clear in Leary and the planet Venus was near its maximum brightness and in the direction described by Carter. Ufologist Robert Sheaffer concluded that the object that Carter witnessed was a misidentification of Venus[4] (Peebles 1994:205). Ufologist Allan Hendry did calculations and agrees with the assessment of it being Venus (Miles 2006:50–52). This could also be the Venus "Halo" [1], as was discussed on The Skeptics' Guide to the Universe podcast #105[5] in a 2007 interview with Jimmy Carter. In the interview Carter stated that he did not believe the object was Venus, explaining that he was an amateur astronomer and knew what Venus looked like. He also said that as a scientist he did not believe it was an alien craft and at the time assumed it was probably a military aircraft from a nearby base. However, he said that the object did not make any sound like a helicopter would do. Carter also said that he did not believe that any extraterrestrials have visited Earth. He also stated he knows of no government cover-up of extraterrestrial visits and that the rumors that the CIA refused to give him information about UFOs are not true.