Detailed Instructions: Generate a correct and concise answer for the question based on the words in the context.
Q: Context : Stephen L. Bettinger (April 28, 1924 -- December 4, 2010) was a United States Air Force flying ace during the Korean War, shooting down five enemy aircraft in the war.
Question : What military branch was Stephen L. Bettinger associated with?
A:
United States Air Force