Lift force is the upward force that allows objects, such as airplanes and birds, to rise and stay in the air. It is generated when air flows over and under the wings or body of the object. The shape of the wings, known as an airfoil, is designed to create a difference in air pressure, resulting in lift. The amount of lift force depends on several factors, including the speed of the object, the density of the air, and the angle of attack, which is the angle between the wing and the oncoming air. Understanding lift force is essential for the design and operation of aircraft and other flying objects.