flier vs aeronaut

flier and aeronaut both are nouns.

Word	Noun	Adjective	Verb	Adverb
flier	Yes	No	No	No
aeronaut	Yes	No	No	No

As nouns, flier and aeronaut are synonyms defined as:

Other synonyms of flier include aviator, flyer.

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