The airport planner working with airports at high elevations is faced with existing conditions that require careful consideration. Of primary concern is the safety of airspace procedures in mountainous areas which are critical and difficult. Very few sites have good obstruction clearances for aircraft approaching the runway or taking off. Another serious consideration is that construction in these areas is expensive, for the airport and for the facilities that are required for it's operation, such as highways, power lines, fuel lines and water supply.This paper describes the experiences and approach of the authors and their associates in undertaking the site selection and master planning for future airport development at Quito, Ecuador which is at 2,812 meters elevation. The city's airport has experienced major impacts from commercial aviation growth in the last two decades. As commercial aircraft traffic increases, the airport is becoming overtaxed physically and environmentally. Major improvements are required to remedy this situation. Since this same problem may be facing other airports in similar regions, our experiences at Quito may be of interest.