airfield vs flying field

airfield and flying field both are nouns.

Word	Noun	Adjective	Verb	Adverb
airfield	Yes	No	No	No
flying field	Yes	No	No	No

As nouns, airfield and flying field are synonyms defined as:

Other synonyms of airfield include field, landing field.

airfield (noun)	flying field (noun)
a place where planes take off and land	a place where planes take off and land