On May 11, 1962, NASA pilot Joseph Walker said that one of his tasks was to detect UFOs during his X-15 flights. He had filmed five or six UFOs during his record breaking fifty-mile-high flight in April 1962. It was the second time he had filmed UFOs in flight. During a lecture at the Second National Conference on the Peaceful Uses of Space Research in Seattle, Joseph Walker said: "I don't feel like speculating about them. All I know is what appeared on the film which was developed after the flight!" - Editor's Note: To date none of those films has been released to the public for viewing.

 

Source: http://www.nationalufocenter.com/artman/publish/article_145.php