There are three axes about which an aircraft can rotate in flight, and therefore it is necessary to have corresponding control surfaces to retain control of the aircraft. An axis is a straight line around which a geometrical figure, in this case an aircraft, can be rotated.
The longitudinal axis is an imaginary line running lengthwise through the nose of an aircraft, to out its tail in the rear. Rotation about the longitudinal axis is called roll. You roll an aircraft by turning the control yoke in the direction you would like it to bank. The control surfaces that accomplish the roll are located at the rear of the main wings near the tips, and are called ailerons. If you wish to bank, or roll, the aircraft to the left, you rotate the control column left. This will raise the left aileron which will drop the left wing, and simultaneously lower the right aileron which will raise the right wing. Of course rotating the control column right will have the opposite effect
The lateral axis is an imaginary line running from wingtip to wingtip. Rotation about the lateral axis is called pitch. You pitch the nose of the aircraft up by pulling back on the control column, and pitch the nose down by pushing forward on the control column. The control surface that accomplishes the movement of pitch is called the elevator, and usually found at the rear of the aircraft at the trailing edge of the horizontal stabilizer. On certain aircraft the horizontal stabilizer and elevator are located in front of the main wing, these aircraft are referred to as canards (French for duck). Canards are actually more efficient than conventional aircraft as a result of the horizontal stabilizer providing lift, while the tail of a conventional aircraft provides down force to stabilize the pitch.
The vertical axis is an imaginary vertical line running through the center of gravity. Rotation about the vertical axis is called yaw. Yawing the aircraft is accomplished by pressing the rudder peddles with your feet, pressing the left rudder peddle yaws the aircraft left and vice versa. The control surface that accomplishes the yaw movement is the rudder, located at the rear of the vertical stabilizer. Pressing the left rudder pedal moves the rudder left, pressing the right one will move the rudder right.
Movement, control, and stability about all three axes are a necessity to safely fly an aircraft, and accomplished by the movement of ailerons, elevator and rudder.