Different notions of amenability on hypergroups and their relations are studied. Developing Leptin's theorem for discrete hypergroups, we characterize the existence of a bounded approximate identity for hypergroup Fourier algebras. We study the Leptin condition for discrete hypergroups derived from the representation theory of some classes of compact groups. Studying amenability of the hypergroup algebras for discrete commutative hypergroups, we obtain some results on amenability properties of some central Banach algebras on compact and discrete groups.Keyword: hypergroups; Fourier algebra; amenability; compact groups; finite conjugacy groups.AMS codes: 43A62, 46H20.In this paper, we investigate different amenability notions of hypergroups and their relations. In particular, we look closer at a generalization of Følner type conditions over hypergroups. This generalization lets us to investigate more structural properties of some classes of hypergroups. In particular we study the existence of bounded approximate identities for the Fourier algebra of regular Fourier hypergroups. We prove a hypergroup analogue of Leptin's theorem for discrete regular Fourier hypergroups that is, the existence of a bounded approximate identity for the Fourier algebra is equivalent to the existence of a square integrable Reiter's net. The later condition is denoted by (P 2 ).We also study amenability of hypergroup algebras (as Banach algebras) for discrete commutative hypergroups satisfying (P 2 ). We show that for this class of hypergroups, the hypergroup algebra cannot be amenable if the inverse of the Haar measure vanishes at infinity. This result and the appearance of (P 2 ) in hypergroup Leptin's theorem emphasize the importance of the amenability notion (P 2 ). At the end we apply these results to some examples of hypergroup structures which are admitted by two classes of locally compact groups, namely compact and discrete groups.1