This is my first time creating a mission, so it's possible I'm out of my league here.
In our mission we have an area that's designated for PvP (We're a free flight server). We don't want players aircraft to leave this area, so I've set up a trigger area that encompasses the area.
We also have two airfields for Red and Blue, and we don't want them shooting each other on the ground so I've set up trigger zones surrounding those airfields as well.
The triggers are as follows:
Type: 1 Once
Event: None
PART OF GROUP OUT OF ZONE (Aircraft name), PvP zone
OR
PART OF GROUP IN ZONE (Aircraft name), red airfield
Then I have it running a script to blow up the aircraft
trigger.action.explosion(Unit.getByName('Pilot #168'):getPosition().p, 100)
Aircraft will sometimes explode when exiting the PvP zone, but never explode upon entering the other airfield.