also: オン・エア · オンエアー · オン・エアー
noun, noun or participle which takes 'suru'
on air; broadcasting
Refers to a program or person currently being broadcast live or recorded for broadcast. Often used in TV/radio contexts.
その番組は今オンエア中です。
That program is currently on air.
新しいCMが来週オンエアされる。
The new commercial will be broadcast next week.
放送 is the general Japanese word for 'broadcast', while オンエア specifically means 'on air' or 'being broadcast', often with a live or real-time nuance.
Loanword from English 'on air'.