cargo helicopter vs whirlybird

cargo helicopter and whirlybird both are nouns.

Word	Noun	Adjective	Verb	Adverb
cargo helicopter	Yes	No	No	No
whirlybird	Yes	No	No	No

As nouns, whirlybird is a hypernym of cargo helicopter; that is, whirlybird is a word with a broader meaning than cargo helicopter:

cargo helicopter: a helicopter that carries cargo
whirlybird: an aircraft without wings that obtains its lift from the rotation of overhead blades

Other hypernyms of cargo helicopter include chopper, eggbeater, helicopter.

cargo helicopter (noun)	whirlybird (noun)
a helicopter that carries cargo	an aircraft without wings that obtains its lift from the rotation of overhead blades