The operator must be able to stop, start, speed up, slow down, and turn the vehicle. This is arranged through systems of control. Trains and highway vehicles and airplanes have wheel brakes. Air or hydraulic pressure pushes pads or blocks against the wheels. Friction produces drag on the wheels to slow or stop the vehicle.
Airplanes also have wing flaps.
They produce air drag and help slow the plane. Ships are slowed or stopped by reversing the propellers. Aircraft engines are also used to slow the plane after landing. The operator must be able to control the amount of power. Acceleration and deceleration controls will vary speed by controlling the amount of fuel delivered to the engine.