The autopilot system was a device or program that provided navigation to a vessel or vehicle without the assistance of a person.
The Dulcinea had an auto pilot system that was used by Cervantes Quinn and Bridget McLellan as they traveled to their next Starfleet Intelligence assignment on the Gorn controlled planet of Seudath. (VAN - Declassified novella: The Stars Look Down)
In the mirror universe Iliana Ghemor managed to steal the starship Githzarai and put the ship on autopilot. Ghemor had also armed an antipersonnel mine on the vessel. The mine detonated, killing the Chalnoth mercenary Grauq and destroying the Githzarai. (DS9 novel: Warpath)