The increasing pressure to cut aircraft emissions in the last decades have resulted in more efficient aircrafts, employing new generation engines and highly advanced wing designs. Nevertheless, as aircraft fleet grows, efficiency gains from both technological and operational improvements will most probably be surpassed. Therefore, even more ambitious improvements shall be necessary to reduce overall aviation impact. In addition, not only pollutant emissions have to be reduced, but also the noise impact on communities in airports’ neighborhood. This might conflict with the goal of lower fuel consumption, and has to be studied case by case. Current in-use departure and approach procedures are far from optimal - even when developed with the aim of being either noise or fuel-efficient. In this work, we present the ongoing research on an online trajectory modeling tool based on optimal control techniques, capable of obtaining and redesigning flight procedures automatically. The objective is to use it for flight planning and replanning, to investigate new trajectories and their impact on airport operations, and to assist pilots before and during the flight. ATM constraint trajectories are studied in a test-case flying from the Amsterdam Airport Schiphol to the Munich Franz Josef Strauss International Airport, with results indicating how they can be improved, offering even more efficient trajectories, with lower noise annoyance impact and lower overall fuel-related emissions.