IDJC is a good alternative to Mixxx for creating live shows. Airtime is a different kind of tool, designed for management of a full 24/7 broadcast schedule in a non-real-time way. Trusted users can be given a show slot in the schedule, and upload content for their forthcoming shows via the web interface, for playout at the correct time. This helps make user generated content and social media broadcasting possible.
This is in contrast to traditional broadcast automation tools, in which music playlists are auto-generated from a format recipe. My suspicion is that the lack of human input might explain why a lot of commercial radio sounds so dull to me. These days, any media player can shuffle a playlist of known songs, so radio has to innovate in order to stay relevant.