A pilot union strike tonight against Lufthansa has caused the airline to preemptively cancel fights to Frankfurt airport in Germany as a majority of the strikers are German pilots. The pilots demand a salary increase of 10% and partial pay after retirement at 60. This pilots already took up a strike last week over the same issues. 20,000 travelers will be affected by this evenings strike.
See "Lufthansa Cancels Flights in Advance of Pilot Strike", Harriet Baskas, USA Today, September 4, 2014