An airplane moves in three dimensions called roll, pitch, and yaw. Roll is rotation about the longitudinal axis that goes down the center of the fuselage. The ailerons control rotation about the roll axis. Pitch is rotation about the lateral axis of rotation, which is an axis parallel to the long dimension of the wings. The elevators control the pitch of the airplane. By controlling the pitch of the airplane, elevators also control the angle of attack of the wing. To increase the angle of attack, the entire airplane is rotated up.
As we will see, this control or the angle of attack is the key to adjustment of the lift of the wings. Finally, yaw, which is controlled by the rudder, is rotation about the vertical axis, which is a line that goes vertically through the center of the wing. It is important to note that all three axes go through the center of gravity of the airplane. The center of gravity is the balance point of the airplane. However, all the weight of the airplane can be considered to be at a single point.