flying saucer vs phantom

flying saucer and phantom both are nouns.

Word	Noun	Adjective	Verb	Adverb
flying saucer	Yes	No	No	No
phantom	Yes	Yes	No	No

As nouns, phantom is a hypernym of flying saucer; that is, phantom is a word with a broader meaning than flying saucer:

flying saucer: an (apparently) flying object whose nature is unknown; especially those considered to have extraterrestrial origins
phantom: something existing in perception only

Other hypernyms of flying saucer include apparition, fantasm, phantasm, phantasma, shadow.

flying saucer (noun)	phantom (noun)
an (apparently) flying object whose nature is unknown; especially those considered to have extraterrestrial origins	something existing in perception only
	a ghostly appearing figure

flying saucer (adjective)	phantom (adjective)
	something apparently sensed but having no physical reality