Complex sentence: He applied to join the South African Air Force at 18 and was rejected but soon travelled to the United Kingdom and was transferred to the RAF in 1936 on a Short Service Commission (SSC).
Split into simpler sentences: He applied to join the South African Air Force at 18 and was rejected but opted for military service. He soon travelled to the United Kingdom and transferred to the RAF in 1936 on a Short Service Commission (SSC).