Complex sentence: Originally developed by UK manufacturer Hawker Siddeley in the 1960s, the Harrier emerged as the only truly successful V/STOL design of the many attempted during that era, despite being a subsonic aircraft, unlike most of its competitors.
Split into simpler sentences: Originally developed by UK manufacturer Hawker Siddeley in the 1960s, the Harrier emerged as the only truly successful V/STOL design of the many attempted during that era. It was a subsonic aircraft, unlike most of its competitors.