Pilots (or auto pilots) are, in essence, rule-based playlists. They automatically generate a list of tracks according to specific rules you have defined. It's an easy way to fill the radio station's program with music during hours where there is no available DJ. Pilots can be as simple or as elaborate as you like. They can range from "shuffle all songs in the library" to things like "play 1 track by AC/DC, then 1 indie rock track, then a track that matches the term 'Heavy Metal' then one track that comes from a soundtrack and then repeat the same recipe".
Here is what a demo pilot looks like:
As mentioned, pilots consist of rules which may include tracks from a tag, keyword, album or an artist. These rules will repeat generating a list of songs for as long as the pilot is scheduled to play. When creating a pilot, you will get an indication of how may times it can create different loops without repeating the same song, or else you will get a warning of '0 matches' if you introduce a rule that matches no tracks. Pay attention in the case that you see the indication "unique loops:0" because this means that you need to re-consider the rules set and check if there are enough tracks matching your rules.
Note that adding more attributes (e.g. tags) in one rule, does not add the number of songs that might match at least one of the attributes, but, on the contrary, confines the criteria to match all of them.
The idea behind pilots is that you can create many pilots based on your zones and you can schedule them. At the management area of the pilots you can see all the available pilots that you have created.
If you don't have something scheduled to air on your program, the default pilot take over. This is a very important function to setup in your radio station. Since you have set the rules for the default pilot, you can, in a sense, have control over what is playing even if you haven't scheduled anything. At the example above, "Ballads" is the default pilot. Note that, if a default pilot is not set at all or has no criteria, it will basically be a randomly generated mix of all the tracks you have uploaded in the Media Library
Check out more on how to create or edit a pilot here.