Place an invisible static object that generates audio of random small arms gunfire within a certain radius

[Tree_Beard]

Just trying to think of ways to make the world seem less empty when you aren't actively flying.

This could add a lot of atmosphere to missions when you are down at low level (out of the cockpit) and there is supposedly a battle taking place around you. 

Place 1 object for sporadic bursts of fire, or overlap several of them for high intensity firefights in the area.

Bonus idea: Allow the player to place a static object that generates streams of tracer fire from point A to point B that the mission designer can drag and drop. How about you can set the interval and number of rounds for each burst, and it keeps happening for the duration of the mission or until a stop condition is triggered. This way you could set up more cinematic/atmospheric missions where forces are concealed in cover and exchanging fire instead of stupidly standing in the open and dying immediately.