on the air
of a radio or television station, program, etc. also on air
: being broadcast（电台、电视台、节目等）正在广播，正在播出 -
The interview will be on the air tomorrow. [=the interview will air tomorrow; the interview will be broadcast tomorrow]这次采访将在明天播出。
-
an interview being shown on air现场采访
-
a show that first came/went on the air [=started being broadcast] five years ago五年前开始播出的一档节目
-
The President went on the air to defend his policies.总统开始电台演讲为他的政策辩护。