We present a method to derive asymptotics of eigenvalues for trace-class integral operators K : L 2 (J; dλ) , acting on a single interval J ⊂ R, which belong to the ring of integrable operators [28]. Our emphasis lies on the behavior of the spectrum {λ i (J)} ∞ i=0 of K as |J| → ∞ and i is fixed. We show that this behavior is intimately linked to the analysis of the Fredholm determinant det(I − γK)| L 2 (J) as |J| → ∞ and γ ↑ 1 in a Stokes type scaling regime. Concrete asymptotic formulae are obtained for the eigenvalues of Airy and Bessel kernels in random matrix theory. K sin (λ, µ) = sin(λ − µ) π(λ − µ) , J sin = (−s, s), s > 0; resp. (1.2) K Ai (λ, µ) = Ai(λ)Ai (µ) − Ai (λ)Ai(µ) λ − µ , J Ai = (s, ∞), s ∈ R; (1.3)