Why is Darkseid afraid of Kryptonians in the dc universe?

Dc Universe Darkseid is afraid of Kryptonians because they can't fly, and Kryptonians can defeat Darkseid.

Darkseid, a powerful being, can't fly, and can only fly by the technology of Apocalypse Star. Darkseid's greatest feature is the omega rays released by his eyes. This is not a simple high temperature or destructive ray, but contains the power of omega rays, which can completely obliterate the existence of opponents or bring them back to life.

Character setting:

Darkseid is the ruler of the apocalypse, the most terrible planet in the multiverse, and the most terrible and powerful evil god in the universe. Second only to his father, he is a powerful new god of Jahan.

It is said that when Mr. Kobe created this role, he almost combined the characteristics of all the power maniacs and tyrants he had ever seen. Among them, 1972, the former US President Nixon who resigned due to the Watergate Incident, was the most famous. His design was based on the appearance of Jack Palance, the best supporting actor in the 1992 Academy Awards.