Reducing emissions is a very prevailing topic also in aviation industry. Besides technological improvements it is necessary to also adjust procedures and operations. We present a tool that is able to optimize flight trajectories not only regarding economical factors but also ecological ones. Due to the utilization of a flight performance model and a detailed engine model, it is possible to determine an aircraft’s emission quantities during all phases of a flight. Besides those like CO2, NOx, CO, Black Carbon, etc. we are also considering contrail formation and their influence on the global warming. By transforming emissions into monetary values we can find a trade off between multiple criteria. After describing the employed models and software architecture we present some use cases where we successfully applied our toolchain.