4.2 Sighting system of fighter aircraft

Issue: World War II fighter aircraft were armed with guns and machine guns. The sights were imperfect, so when firing a machine gun, the pilot had to adjust the sight by the visible path of glowing bullets. When more powerful aircraft guns were used, it was impossible to adjust the sight by the visible path, because the strong recoil of the gun instantly disrupted the aim.

It was not easy to aim in advance using a primitive sighting unit. Aiming along a visible path of gun bullets was impossible and uneconomical.

Question: What is to be done?