Tens of thousands of passengers were set to have their travel plans disrupted again on Thursday due to strikes by aviation security staff at five German airports, according to industry estimates. According to a spokesman for the trade union verdi, Thursday’s all-day strike by aviation security staff at the airports in Hamburg, Stuttgart, Karlsruhe/Baden-Baden, Cologne and Berlin had started. The union also called for further strikes by aviation security staff on Friday. According to estimates by the airport association ADV, more than 580 flights are likely to be cancelled and 90,000 travellers…