aircraft carrier vs war vessel

aircraft carrier and war vessel both are nouns.

Word	Noun	Adjective	Verb	Adverb
aircraft carrier	Yes	No	No	No
war vessel	Yes	No	No	No

As nouns, war vessel is a hypernym of aircraft carrier; that is, war vessel is a word with a broader meaning than aircraft carrier:

aircraft carrier: a large warship that carries planes and has a long flat deck for takeoffs and landings
war vessel: a government ship that is available for waging war

Other hypernyms of aircraft carrier include combat ship, warship.

aircraft carrier (noun)	war vessel (noun)
a large warship that carries planes and has a long flat deck for takeoffs and landings	a government ship that is available for waging war