Globally, aviation accounts for a modest share of World total greenhouse gas (GHG) emissions from today’s energy use. However, air transport has been rapidly increasing and many other sectors are expected to reduce their emissions. Hence, aviation’s share of global emissions can be foreseen to rise and will constitute a significant part of the problem unless strong counteracting initiatives are taken. Efforts regarding aviation have so far been limited, although despite significant technological improvements of aircraft energy efficiency over the past decades. The Nordic countries all have high ambitions to become more environmentally sustainable. The aim of this report is to examine challenges and opportunities for increased Nordic cooperation with regards to increasing sustainability of aviation and, based on evaluation of alternative options, propose common policy measures.