Air transport systems evaluation infrastructure (IESTA) is an evaluation facility for air transport systems that is currently being developed by Onera in Toulouse, France. The project aims at building a generic simulation platform, designed to ease the integration of new or existing models in order to assess air transport concepts. The first IESTA application, Clean Airport, allows the assessment of the effects of innovative concepts with regard to air traffic noise and chemical pollution on the airports' surroundings. An effective simulation capability has been built and achieved by integrating Onera's expertise in physical modelling. This article gives an overview of the resulting model toolbox architecture, the first outputs and the validation walkthrough.