For instance, every airplane must be equipped with a landing light. If the landing light is installed on the fuselage or a wing, the air resistance increases, which reduces the airplane speed. When the landing light is placed inside a wing and covered with a transparent fairing, the design becomes too complex and the wing's strength reduces.
Designers have found a simple way of resolving this contradiction in the temporal aspect. The landing light is attached to the strut or to the cover plates of the landing gear hole. Before landing, when the airplane extends the landing gear, the landing light is brought into a normal position and illuminates the site.

Another contradiction arises between the position of the arms carried by a fighter airplane and its head resistance. The more arms on an airplane, the stronger the airplane is in flight. At the same time, the area of its head projection increases and its streamline from is impaired. The airplane speed and fight efficiency are reduced.
In "Sabre" - one of the first American jet fighters, this contradiction is resolved in the following way. A multi-barreled battery of rocket projectiles is placed in the fuselage, under the pilot's cabin. When the pilot reaches an effective shooting range, the launcher is drawn out of the fuselage and a rocket projectile is launched.