You can reduce the attributes of the enemy units through:

- Upgrading the AC-130 equipment inside the Airport.
- Increasing the levels of AC-130 crew members inside the Airport.
- Completing some of the AC130 technology research inside the Research Institute.
- Installing widgets with reduction attributes such as HP, attack, or defense.
- Increasing the Honor level in your base.

And there are many other ways that you can discover as you delve deeper into the game.