Target Pass Through Trigger Tutorial.
I recommend reading this tutorial first. >>
http://forum.1cpublishing.eu/showthread.php?t=28454
This allows you to set trigger events when aircraft fly through a defined area.
This example shows Defiants triggered to spawn and attack when He111's flying into the Target Trigger Area.
This tutorial assumes you have read the above example from FG28 Kodiak as the
script spawn Only applies to the Defiants.