air alert vs alert

air alert and alert both are nouns.

Word	Noun	Adjective	Verb	Adverb
air alert	Yes	No	No	No
alert	Yes	Yes	Yes	No

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

air alert: the warning signal that begins a period of preparation for an enemy air attack
alert: an automatic signal (usually a sound) warning of danger

Other hypernyms of air alert include alarm, alarum, warning signal.

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

air alert: the condition in which combat aircraft are airborne and ready for an operation
alert: condition of heightened watchfulness or preparation for action

Other hypernyms of air alert include qui vive.

air alert (noun)	alert (noun)
the warning signal that begins a period of preparation for an enemy air attack	a warning serves to make you more alert to danger
the condition in which combat aircraft are airborne and ready for an operation	an automatic signal (usually a sound) warning of danger
the time period during which military and civilian agencies are prepared for an enemy air attack	condition of heightened watchfulness or preparation for action

air alert (adjective)	alert (adjective)
	engaged in or accustomed to close observation
	mentally perceptive and responsive
	quick and energetic

air alert (verb)	alert (verb)
	warn or arouse to a sense of danger or call to a state of preparedness