Complex sentence: The Panther was the most widely used U.S. Navy jet fighter of the Korean War, flying 78,000 sorties and scoring the first air-to-air kill by the US Navy in the war, the downing of a North Korean Yakovlev Yak-9 fighter.
Split into simpler sentences: The Panther was the most widely used U.S. Navy jet fighter of the Korean War. It flew 78,000 sorties and was responsible for the first air kill by the US Navy in the war--the downing of a North Korean Yakovlev Yak-9 fighter.