Radio-frequency electromagnetic waves, usually used in the context of wireless communication; radio waves.
Radio or television broadcasts.
1989 December 10, Melanie Berzon et al., “Boston Women's Community Radio To Break For 1990”, in Gay Community News, volume 17, number 22, page 4:
Our goal has always been to work as allies with women who do not have access to the mainstream airwaves. We have tried to provide a forum where women could speak for themselves about the issues that concern them.
2006 August 25, Xubo Jiang, “Amateur radio enthusiasts search for missing mum”, in Beijing Review, number 273, →ISSN, →OCLC, page 2, column 1: