Renewed strikes by security staff brought operations at five German airports to a virtual standstill on Thursday. The airports affected were Berlin, Hamburg, Stuttgart, Karlsruhe/Baden-Baden and Cologne/Bonn, where the industrial action began on Wednesday evening. All departures were cancelled at the airports because passengers and goods could no longer pass through security checks. There were also numerous cancellations of landings. According to estimates by the airport association ADV, more than 580 flights are likely to have been cancelled and 90,000 travellers will have to reschedule. The …