An airplane throttle, or power lever, is a type of stick with a ball-shaped topper positioned behind the cockpit’s firewall, similar to how a regular passenger vehicle’s gearshift is often positioned behind the vehicle’s dashboard. The throttle controls the airplane’s power level by controlling how much air or air/fuel mixture the cylinders receive. The closer to the firewall the pilot pushes the throttle, the more power the airplane has. When a pilot wants full power, he pushes the throttle all the way forward, toward the firewall. Therefore, when pilots push their throttles all the way forward to achieve full power, they are said to have pushed the balls to the walls.
