One of the potentially most significant ways of decreasing emissions at airport is by towing the aircraft on the ground instead of using its main engines. In this paper we will give a high level overview of what the potential average and marginal fuel savings and impact on emissions is for some of the larger airports in Europe and the US. Especially for large hub airports, the savings are significant and are very likely more than enough to make the benefit of fuel saved outweigh the investment and cost of operating a fleet of towing vehicles.