This story keeps kicking around my head and it's irritating because I only remember a little bit of it and can't find it to read all of it. I know it's a do-over story where the MC goes back in time (not far, maybe his own life-time). I think he uses his knowledge to get rich, but I won't swear to that. The only part that I remember is that he's on one of the flights that gets hijacked on 9/11 and suddenly remembers it when he sees one of the hijackers heading for the cockpit. He gets up and attacks the hijacker and gets stabbed (or gets his throat cut, I can't remember). I think that was the end of the story, but I'm not sure.
I'm hoping somebody can help me out. Thanks in advance.