Strategies:-
The Ballista, brother to the Arbalest is a Mechanical-based Mobile Artillery, just like the Arbalest. Difference is that its role is to decimate the Air while the Arbalest takes the land. Ballistas are very rarely seen in Rocs as they can move fairly faster than the Arbalest. Their high velocity shells that are shot from the turrets can decimate a small group of weak Aviation Units.

Bombard Aviation:-
While they may lack the versatility of the Trebuchet, the Ballista can deal lots of damage on weak Aviation Units and can clear out enemy Rocs from a long distance and wait for allied Aviation to clear what's left of it. The concept of the Ballista is the same as the Arbalest. Hold "CRTL" and click to aim where you want to shoot. Press "A" to deploy and Air Bombard the area. Remember, you must be fast as most Aviation Units are very fast. Though it can Air Bombard, the Ballista cannot fire at cloak units, provided that a sensor is not present.