also: オンジエア
noun
on the air; broadcasting
Borrowed English phrase used in Japanese broadcasting contexts to mean a program is currently being transmitted live or recorded for broadcast.
そのラジオ番組は毎週土曜日にオン・ジ・エアです。
That radio program is on the air every Saturday.
生放送中
During the live broadcast, the 'on the air' sign lights up.