Drones are small robots used to support and supplement organic soldiers on the battlefield. They have no Artificial Intelligence of any kind but follow fixed, minimally adaptive programs. Most varieties employ mass effect levitation to improve mobility.
All modern armies rely on veritable fleets of drones for routine soldiering (static garrisons, patrols, etc.). The use of drones in non-critical duties keeps manpower need down and reduces casualties in low intensity conflicts. Less advanced races and cultures with less sensitivity to casualties have correspondingly few drones in their inventory. Drones are of little use in conventional open field battles, as they are poorly armed and armored.
In addition to combat drones, support drones are used to assist organic units in the field. Reconnaissance drones are small, stealthy craft that screen combat units in the field and warn commanders when enemies are spotted. Electronic Warfare drones supplement battlefield technicians, serving as mobile jammers and ELINT (ELectronic INTelligence) gathering platforms. Military and civilian police utilize "dazzler drones" equipped with powerful strobe lights to disorient and subdue intruders using nonlethal force.
Drone formations are officially referred to as wings, (i.e. "Deploy the 4th Assault Drone Wing on the left flank"). Common soldiers often refer to friendly formations as flocks and enemy formations as swarms.