Complex sentence: Renamed the X- 15A-2, this plane first flew on 28 June 1964, reaching a maximum speed of in October 1967, flown by William "Pete" Knight of the U.S. Air Force.
Split into simpler sentences: Renamed the X- 15A-2, this plane first flew on 28 June 1964. It reached a maximum speed of in October 1967 while being flown by William "Pete" Knight of the U.S. Air Force.