The primary flight controls are the ailerons, elevators, and rudder. The ailerons and elevators are operated from the cockpit by a control stick on fighter aircraft. A wheel and yoke assembly is used on large aircraft such as transports and patrol planes. The rudder is operated by rudder pedals on all types of aircraft.

The ailerons are operated by a lateral (side-to-side) movement of the control stick or a turning motion of the wheel on the yoke. The ailerons are interconnected in the control system and work simultaneously, but in opposite directions to one another. As one aileron moves downward to increase lift on its side of the fuselage, the aileron on the opposite side of the fuselage moves upward to decrease lift. This opposing action allows more lift to be produced by the wing on one side of the fuselage than on the other side. This results in a controlled movement or roll because of unequal forces on the wings. The aileron system can be improved with the use of either powered controls or alternate control systems.

The elevators are operated by a fore-and-aft movement of the control stick or yoke. Raising the elevators causes the aircraft to climb. Lowering the elevators causes it to dive or descend. The pilot raises the elevators by pulling back on the stick or yoke and lowers them by pushing the stick or yoke forward.

The rudder is connected to the rudder pedals and is used to move the aircraft about the vertical axis. If the pilot moves the rudder to the right, the aircraft turns to the right; if the rudder is moved to the left, the aircraft turns to the left. The pilot moves the rudder to the right by pushing the right rudder pedal, and to the left by pushing the left rudder pedal.

Power control systems are used on high-speed jet aircraft. Aircraft traveling at or near supersonic speeds have such high air loads imposed upon the primary control surfaces that the pilot cannot control the aircraft without power-operated or power-boosted flight control systems. In the power-boost system, a hydraulically operated booster cylinder is incorporated within the control linkage to assist the pilot in moving the control surface. The power-boost cylinder is still used in the rudder control system of some high-performance aircraft; however, the other primary control surfaces use the full power-operated system. In the full power-operated system, all force necessary for operating the control surface is supplied by hydraulic pressure. Each movable surface is operated by a hydraulic actuator (or power control cylinder) incorporated into the control linkage.

In addition to the current Navy specification requiring two separate hydraulic systems for operating the primary flight control surfaces, specifications also call for an independent hydraulic power source for emergency operation of the primary flight control surfaces. Some manufacturers provide an emergency system powered by a motor-driven hydraulic pump; others use a ram-air-driven turbine for operating the emergency system pump.