Various measures ensure reduce aircraft noise during the approach: Read more here about 
Flight routes
DFS German Air Navigation Services essentially develops approach routes based on the same criteria as departure routes.
One difference is that controlling approaching traffic is the sole responsibility of DFS. The German Air Traffic Regulations (LuftVO) authorize air traffic controllers to individually determine the flight course, in particular the flight path and altitude. Using radar and maintaining prescribed safety distances, the air traffic controllers guide the approaching aircraft from the various directions and altitudes through the turning areas into the airport’s terminal maneuvering area. From there, aircraft follow the beams of the instrument landing systems (ILS) for the final approach.
Flight courses may in some cases deviate significantly from ideal route lines and go outside of the turning areas. This is because air traffic controllers guide approaching planes individually in line with the current requirements of the respective air traffic situation. The main turning areas to the east and west extend further when traffic volumes are high than when they are low. Outside the main turning areas, turning areas are defined for the downwind approach lines. How frequently these outer turning areas are used also depends on the traffic volume.
Planes take off on the instrument departure routes, which DFS plans in consultation with the Aircraft Noise Commission.
The German Federal Air Traffic Controlling Office (BAF) issues approval. The key criteria here are safety, practical applicability by pilots and air traffic control, and noise reduction.
Various measures ensure reduced aircraft noise during take-off: Read more here about
Pilots act in line with regulations as long as they keep their aircraft within the respective route corridor or tolerance area around a route. The route corridor is specified in line with guidelines of the International Civil Aviation Organization (ICAO). If the pilot demonstrably leaves the corridor without good reason, DFS will apply to BAF for the instigation of administrative offense proceedings against the pilot responsible.
In safety-relevant situations such as a storm, deviations from the noise reduction route are necessary and therefore permitted. Pilots can leave the departure route above a specific altitude if they have asked DFS for approval.
