A strike by airport ground staff has paralysed operations at five German airports on Wednesday as part of an ongoing wage dispute with the country’s largest airline Lufthansa. Lufthansa has cancelled up to 90% of its approximately 1,000 flights scheduled. The airline spoke of 100,000 affected passengers. At major hubs Frankfurt and Munich, less than half of the usual flights took place as Lufthansa is the main operator there. Trade union Verdi on Wednesday threatened to extend its strikes if the airline’s executive board does not significantly improve its current wage offer for ground staff. T…