airway vs air duct

airway and air duct both are nouns.

Word	Noun	Adjective	Verb	Adverb
airway	Yes	No	No	No
air duct	Yes	No	No	No

As nouns, airway and air duct are synonyms defined as:

Other synonyms of airway include air passage.

airway (noun)	air duct (noun)
a commercial enterprise that provides scheduled flights for passengers	a duct that provides ventilation (as in mines)
a duct that provides ventilation (as in mines)
the passages through which air enters and leaves the body
a designated route followed by airplanes in flying from one airport to another