headwind vs air current

headwind and air current both are nouns.

Word	Noun	Adjective	Verb	Adverb
headwind	Yes	No	No	No
air current	Yes	No	No	No

As nouns, air current is a hypernym of headwind; that is, air current is a word with a broader meaning than headwind:

headwind: wind blowing opposite to the path of a ship or aircraft
air current: air moving (sometimes with considerable force) from an area of high pressure to an area of low pressure

Other hypernyms of headwind include current of air, wind.

headwind (noun)	air current (noun)
wind blowing opposite to the path of a ship or aircraft	air moving (sometimes with considerable force) from an area of high pressure to an area of low pressure