I see in the Data you have a section for Airfield Guards.  If I manually spawn a Bradley there your mod works as advertised.  NICE!

However, how I set up random Bradley events are Airfield?  Is there a mod for this or do I need to run some commands when the server starts?

Spawning bradley at airfield can be done via Custom Map or Plugin, Bradley Guards just has support to setup the event Guard event at each monument you specify.