Campaigns deliver ads via flights. 

Flights capture the ad configuration itself and can feature one or more creative audio files to play in place of an ad marker (cue-point), or at the beginning or end of the episode.

Each time a flight places an ad into the episode, it will be tracked against the campaign for a precise measurement of how your campaign is going.

A flight can contain any audio either uploaded directly into it or reused from the Media Library.