Almost 640 flights were cancelled in Germany Thursday as security staff went on strike at three airports, meaning disruption for over 100,000 passengers. The number of flights blocked was more than half the 1,050 planned for Düsseldorf, Cologne-Bonn and Stuttgart. Düsseldorf -- the country's third-largest airport -- said in a statement that 370 of Thursday's 580 planned departures had to be cancelled. The walkout, slated to last from 3:00 am to midnight, is expected to affect around 110,000 travellers, according to DPA. At Cologne-Bonn, where 131 of almost 200 flights were cancelled. Union Verdi told DPA the security strike was also slowing freight handling. In Stuttgart, 142 of the 270 take-offs and landings were cancelled, in Düsseldorf as many as 350 out of 570. In Berlin, slightly over 90 at both airports were cancelled.