Historical development of commercial flight movements per year

Air traffic at airports and airfields is subject to various seasonal fluctuations.
The monthly operating performance will depend on holiday periods and weather conditions, among other things. Passenger numbers at large airports peak during the spring and summer months, whereas they usually fall below capacity in November.
A breakdown according to days of the week will show a fairly balanced picture for national airports. The only striking feature is that the average volume of traffic is lower on Saturdays than on Fridays and Sundays. Regional airports are busier at weekends due to leisure activities.
If traffic volume is considered in terms of time of day, it becomes clear that operations are concentrated around daytime hours. Off-peak hours are particularly used for long-haul flights due to coordination with the intra-European short-haul traffic.
In general, there is a ban on night flights. For example, Zurich-Kloten has a ban that lasts from 11:30 p.m. to 6 a.m., whereby the time between 11 p.m. and 11:30 p.m. can only be used for reducing flight delays. At Geneva Airport, take-offs and landings of commercial flights are authorized between 06:00 and 23:59. Nighttime period runs from 22:00 to 00:00. After 23:59, aircraft that are behind schedule are allowed by law to take-off or land until 00:29.
Several flights are subject to no restrictions. This is particularly the case with distress landings, as well as take-offs and landings related to search and rescue flights, ambulance and police flights, relief flights in case of disaster, flights of Swiss military aircraft and flights of State owned aircrafts authorised by the Federal Office of Civil Aviation (FOCA).
Noise levels caused by flight movements are recorded and documented at a number of measuring points located around the large airports. The noise is measured so that a range of measures can be implemented to keep emissions as low as possible.