In your keyboard mapping is a command for setting the player you first did this to:
.wingman playerID
As the formation leader which your fighter or bomber will then be controlled by as a robot.
You need to assign that command a hotkey. Once you have a hotkey set for it.
1. - .wingman playerID
2. - get within 1000-400 yards and hit your mapped hotkey.
From that point until you break free, your wingman will control your plane as long as his maneuvers are gentle. This is great for large formations of bombers with players who don't know how to use the bomb sight calibration very well. They just wait until the mission leader(.wingman) tells them to start hitting their bomb drop button.
It's better to first form up at about half throttle. Some players find the gyrating around of their virtual in cockpit stick our yoke disturbing that takes place during this.
The new key is Auto Pilot Wingman. I think I assigned Ctrl_W to it.