US Air Force vs Air Force

US Air Force and Air Force both are nouns.

Word	Noun	Adjective	Verb	Adverb
US Air Force	Yes	No	No	No
Air Force	Yes	No	No	No

As nouns, US Air Force and Air Force are synonyms defined as:

US Air Force and Air Force: the airforce of the United States of America; the agency that defends the United States through control and exploitation of air and space

Other synonyms of US Air Force include U. S. Air Force, United States Air Force, USAF.

US Air Force (noun)	Air Force (noun)
the airforce of the United States of America; the agency that defends the United States through control and exploitation of air and space	the airforce of the United States of America; the agency that defends the United States through control and exploitation of air and space