air force vs Air Corps

air force and Air Corps both are nouns.

Word	Noun	Adjective	Verb	Adverb
air force	Yes	No	No	No
Air Corps	Yes	No	No	No

As nouns, Air Corps is a hyponym of air force; that is, Air Corps is a word with a more specific, narrower meaning than air force:

Other hyponyms of air force include RAF, Royal Air Force, German Luftwaffe, Luftwaffe.

air force (noun)	Air Corps (noun)
the airborne branch of a country's armed forces	formerly the airborne division of the United States Army