And that it's quite plausible that at least one Me-262 broke the sound barrier towards the end of WWII?
And that it's most likely that George Welch went over Mach 1 in the XP-86 Sabre, weeks before Chuck Yeager did the "Right Stuff" ?
It has been recognised that George Welch was the first. Chucks claim to fame is being the first to do it in level flight (Mach 1 that is). As to the 262, the claim that it did,or may have, has been put to rest as a no. There is a comprehensive post war test report done in the US somewhere on the web.