SAS is an AI application developed for the Hong Kong International Airport (HKIA) at Chek Lap Kok. SAS uses constraint-programming techniques to assign parking stands to aircraft and schedules tow movements based on a set of business and operational constraints. The system provides planning, real-time operation, and problem solving capabilities. SAS generates a stand allocation plan that finely balances the objectives of the airlines/handling agents, the convenience of passengers, and the operational constraints of the airport. The system ensures a high standard of quality in customer service, airport safety, and utilization of stand resources. This paper also describes our experience in developing an AI system using standard off-the- shelf software components. SAS is an example of how development methodologies used to construct modern AI applications have become fully inline with mainstream practices.