travelling vs aviation

travelling and aviation both are nouns.

Word	Noun	Adjective	Verb	Adverb
travelling	Yes	No	No	No
aviation	Yes	No	No	No

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

travelling (noun)	aviation (noun)
the act of going from one place to another	travel via aircraft
	the art of operating aircraft
	the aggregation of a country's military aircraft
	the operation of aircraft to provide transportation