A simple description of air transportation could be based on three elements: the aircraft, the airport, and the air navigation system. The first transports people and goods; airports allow passengers and goods to change transportation mode; the later provides services to ensure air operations are performed in a safe way. The activities of each of these three elements have a characteristic environmental impact, including construction, life-cycle, and reposition. A introductory reference on the topic is BENITO and BENITO . Even though the different environmental impact sources will be briefly described, the focus will be on aircraft operations’ environmental fingerprint, in particular to its contribution to climate change. The reader is referred to Schumann  for a recent, thorough overview.