Who are the big 5 in aerospace?

Could you please elaborate on the "big 5" in the aerospace industry? Are you referring to the top five aerospace manufacturers globally, or perhaps the most influential companies in terms of technology, innovation, or market share? Additionally, how do these companies compare in terms of their product offerings, such as commercial aircraft, military aircraft, or space exploration technologies? Understanding the context of your question would help me provide a more accurate and informative answer.