On air is an expression that is commonly used in the media industry to describe the broadcasting of live programs, events, or shows. However, there are several alternative words that can be used instead of "on air." These include "live," "broadcasting," "streaming," "airing," and "telecasting." All of these words convey the idea of something being broadcasted to the public through various media channels such as TV, radio, or online platforms. In addition, these words can also be used interchangeably, depending on the context and the medium of communication being used, to describe the transmission of information, entertainment, or news to the audience.