propagation vs airing

propagation and airing both are nouns.

Word	Noun	Adjective	Verb	Adverb
propagation	Yes	No	No	No
airing	Yes	No	No	No

As nouns, airing is a hypernym of propagation; that is, airing is a word with a broader meaning than propagation:

propagation: the spreading of something (a belief or practice) into new regions
airing: the opening of a subject to widespread discussion and debate

Other hypernyms of propagation include dissemination, public exposure, spreading.

propagation (noun)	airing (noun)
the act of producing offspring or multiplying by such production	the act of supplying fresh air and getting rid of foul air
the spreading of something (a belief or practice) into new regions	a short excursion (a walk or ride) in the open air
the movement of a wave through a medium	the opening of a subject to widespread discussion and debate