airplane vs bomber

airplane and bomber both are nouns.

Word	Noun	Adjective	Verb	Adverb
airplane	Yes	No	No	No
bomber	Yes	No	No	No

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

airplane: an aircraft that has a fixed wing and is powered by propellers or jets
bomber: a military aircraft that drops bombs during flight

airplane (noun)	bomber (noun)
an aircraft that has a fixed wing and is powered by propellers or jets	a military aircraft that drops bombs during flight
	a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States
	a person who plants bombs