Supersonic/Hypersonic air intake performance is defined in terms of intake capability and efficiency. This work mainly deals with an intake starting characteristic for different contraction ratio of hypersonic vehicles. The strong-shock design principle is proposed on the basis of comparison of the limiting contraction line with the Kantrowitz (self-starting) lines of a few particular ramp intakes. Our study is based on varying area contraction ratio (1, 1.5, 1.7, 2 and 2.5) and to find the best performance of intake starting condition for both symmetry (2D) and axisymmetric (3D) for various Mach numbers. During research work, we found that intake starting problem for symmetry to axisymmetric is not same, it may start in axis symmetric whereas in symmetry, it may lead to unstart. This paper represents the study on different area ratio configuration for start flow in the air intake.