Complex sentence: McCampbell is the U.S. Navy's all-time leading flying ace and top F6F Hellcat ace with 34 aerial victories and the third-highest American scoring ace of World War II and the highest-scoring American ace to survive the war.
Split into simpler sentences: McCampbell is the United States Navy's all-time leading flying ace and top F6F Hellcat ace with 34 aerial victories. He was the third-highest American scoring ace of World War II and the highest-scoring American ace to survive the war.