Aircraft taxiing on the surface contribute significantly to the fuel burn and emissions at
airports. This report is an overview of PARTNER’s Project 21, which tries to identify promising
opportunities for surface optimization to reduce surface emissions at airports, estimate the
potential benefits of these strategies, and assess the critical implementation barriers that need
to be overcome prior to the adoption of these approaches at airports. We also present a new
queuing network model of the departure processes at airports that can be used to develop
advanced queue management strategies to decrease fuel burn and emissions
