This is an old revision of the document!
Many power armors can either jump-jet or maintain flight indefinately - making them comparable with helecopter gunships or even VTOL capable fighter jets.
This adds a new dimension to the battlefield: Who is above you? Who can see you from below?
Can you afford to be seen or shot by either?
Think like a pilot. Altitude. Heading. Way-points. Speed. Even fighter-jet maneuvers can get you out of a pinch if you're moving quickly enough.
Motion at lower speeds (especially in high end armor) tends to be much closer to what we know now as UFO - taking short controlled horizontal bursts of motion to evade enemy weapons fire - chaining these motions into evasive patterns and rapidly changing direction.
Missiles and high-velocity weapons are king in the air thanks to the vast space they need to be used properly. Particle weapons can also be used but they tend not to go the distances they would in space. Air-burst weapons can make ideal counter-measures and distractions - even as far as to throw your enemy off his projected course and knock him to the ground.
If you can't hit your enemy, surpress him and back him into a corner on the ground and make sure he can't get airborne. If you lack the armor to hurt your enemy, you should consider the impact of knocking them to the ground at speed or the vast range around you: you could easily have support measures in place - even from space.
Attacking ground units from the air is highly advantageous - High-yield rockets are supremely capable in this role - even if only as a distraction - using the space normally used for guidance to house additional munitions - hence they can be very small and easily transported in big numbers or hidden.