stealth aircraft vs aircraft

stealth aircraft and aircraft both are nouns.

Word	Noun	Adjective	Verb	Adverb
stealth aircraft	Yes	No	No	No
aircraft	Yes	No	No	No

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

stealth aircraft: an aircraft designed in accordance with technology that makes detection by radar difficult
aircraft: a vehicle that can fly

stealth aircraft (noun)	aircraft (noun)
an aircraft designed in accordance with technology that makes detection by radar difficult	a vehicle that can fly