airtime

or air time

[ air-tahym ]
/ ˈɛərˌtaɪm /

noun

the particular time that a program is broadcast or scheduled for broadcast: The airtime for the newscast is 10 p.m.
the time during which a broadcast takes place: The airtime for the new show is from 10 to 10:30 p.m.
a block of such time sold by a radio or television station to an advertiser, allotted to a political candidate, etc.: The company bought three minutes of airtime.

Origin of airtime

First recorded in 1940–45; air1 + time

British Dictionary definitions for air time

airtime
/ (ˈɛəˌtaɪm) /

noun

the time allocated to a particular programme, item, topic, or type of material on radio or television
the time of the start of a radio or television broadcast