flier vs traveller

flier and traveller both are nouns.

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

As nouns, traveller is a hypernym of flier; that is, traveller is a word with a broader meaning than flier:

Other hypernyms of flier include traveler.

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