The operator is the one who operates the flight between an origin and a destination.
When you buy your ticket LATAM has different operators that can be:
<ul>
<li style="font-weight: 400;" aria-level="1">LATAM Airlines Group</li>
<li style="font-weight: 400;" aria-level="1">LATAM Airlines Chile</li>
<li style="font-weight: 400;" aria-level="1">LATAM Airlines Peru</li>
<li style="font-weight: 400;" aria-level="1">LATAM Airlines Colombia</li>
<li style="font-weight: 400;" aria-level="1">LATAM Airlines Ecuador</li>
<li style="font-weight: 400;" aria-level="1">LATAM Airlines Brazil</li>
<li style="font-weight: 400;" aria-level="1">LATAM Airlines</li>
</ul>

What is the flight operator?