flyer vs airman

flyer and airman both are nouns.

Word	Noun	Adjective	Verb	Adverb
flyer	Yes	No	No	No
airman	Yes	No	No	No

As nouns, airman is a hyponym of flyer; that is, airman is a word with a more specific, narrower meaning than flyer:

Other hyponyms of flyer include airwoman, aviatress, aviatrix, airplane pilot, pilot.

flyer (noun)	airman (noun)
an advertisement (usually printed on a page or in a leaflet) intended for wide distribution	a male who operates an aircraft
someone who travels by air
someone who operates an aircraft