I was on UA 6452 from TUS-LAX today. Landing at LAX, we were almost touched down when the pilot aborted the landing, pulled back the flight full throttle and said it was due to another plane on the runway.

Needless to say, we ended up having a fly around LAX for about 20 minutes. The pilot would not say how close it was. It's happened to me before several times, but I'd be curious to find how if it was a "near miss".