Abstract
With increasing focus on global environment and energy, sustainability of aviation is becoming one of substantial challenges in world transportation, especially considering significant increase in future air transport demand. Firstly, this paper describes impacts on global/local environment and energy of aviation, then discusses about recent governmental and civil efforts to reduce such impacts, including studies on the use of alternative fuel. Overviewing some future civil air transport concepts, technical challenges in aerodynamics are addressed, emphasizing aerodynamic drag reduction techniques.