An automotive seat or an airplane passenger seat is used by thousands or millions of people. The seat should be designed to accommodate the maximum number of a target population by taking into account the variability of body size in the population and also the environment’s constraints. Thanks to a fully adjustable experimental seat recently built at IFSTTAR, data of the optimal seat profile parameters and compressed seat pan surface were collected in function of seat pan and backrest angle from a sample of 36 differently sized participants. Parametric models were obtained to predict optimal seat profile parameters in function of a sitter’s anthropometric characteristics, seat pan angle and seat back angle. Using a population simulation approach, a sample of 500 males and 500 females were generated randomly based on the distribution of relevant anthropometric dimensions. The optimal seat profile parameters such as seat height, seat pan length, back profile angle as well as optimal compressed seat pan surface were suggested based on their distribution obtained by simulation. The aim of the paper is to present the population simulation approach and optimal seat profile for airplane eco-class passenger seats.