Autopursuit

Autopursuit (also called Auto-track) is a flight-assist system that allows the player's ship to match direction and speed with its target.

The default key assignment is for gamepads and  for Keyboard+Mouse. By holding down that trigger/button your ship will rotate around to head directly towards the target and after getting close to the target your ship will move behind the target and align its speed as well. After a while you will essentially be flying behind the target at the same speed. In combat this allows you to follow your target in a more automated manner (compared to regular movement by using the gamepad/mouse/joystick), even if the erratic nature of the enemy ship's movement does not allow for clean alignment, but rather a constant approach to the best possible position for shooting. The Maneuverability of your ship has a big impact on how fast your ship can align towards the target.

For waypoints and distant targets the Autopursuit is mainly used to quickly orientate your ship towards them without the need to scan the 3D space for the correct approach vector.