Flights at Frankfurt airport between 23:00 and 05:00 are banned by a decision of an administrative court in the Federal State Hesse. Along with a total ban from 11 pm to 5 am, the Leipzig court also reduced the number of flights permitted in the period covering the so-called shoulder hours from 10 pm to 6 am to 133 from 150. http://www.reuters.com/article/2012/04/04/uk-frankfurt-nightflights-idUSLNE83300W20120404