I was watching the Discovery Channel program comparing the
F-86 and Mig-15 and heard that the F-86 can break the sound
barrier. I know that this has been claimed many time before
but is that the official position of the US Air Force?

Certainly the F-86 can break the sound barrier in a shallow dive. Many pilots
got thier first taste of sonic flight that way. I have read that a Canadian
pilot used to open airshows by doing just that in the days before sonic booms
were outlawed in most areas.

Is Yeager still officially the first man to break the sound
barrier?

Yes. Though anecdotal evidence suggests strongly that George Welch was
probably the first pilot to break the sound barrier there will probably never
be any way to prove it in the same way that Yeager's flight was. Apparently
though some time ago the Air Force took to qualifying Yeager's flight as the
first sustained supersonic flight in level attitude.

John Dupre'