The aim of this study is to establish a nation-wide cost-benefit framework for aviation projection appraisal. This framework is built upon Transportation System Analysis Model developed at Virginia Tech Air Transportation System Model (TSAM). Both supply and demand characteristics and their inter-dependence are investigated. It attempts to solve the absence of supply constraints in aviation demand forecast in the literature. In addition, external costs in term of noise and emission are also considered. A national environmental impact analysis introduced by new generation small aircraft system is conducted. Two case studies are discussed to illustrate the framework. The first one is based on the GPS Wide Area Augmentation System (WAAS) Lower Landing Minima capability. It represents a nation-wide cost-benefit analysis with examination of both supply and demand. System-wide benefit of accessibility improvement and infrastructure cost are scrutinized at the same time. A prioritized set of candidate airports for this technology is provided as a result. The second study focuses on New York area. Benefits brought by DataComm technology are evaluated by multi-iteration simulations. DataComm is projected to reduce entry point intrail and final approach separation. The improvements are modeled at individual airport and New York airspace. Consumer surplus is estimated based on demand and delay relationship using TSAM.Ph. D.