Local public transit workers in around 80 German cities and towns are staging a day-long strike on Friday, in the latest show of labour unrest in Europe’s largest economy. Riders have been warned to expect diminished or no service on bus, tram and underground lines in cities across Germany, with the exception of Bavaria. The action comes a day after airport security staff walked off their jobs at 11 German airports. Last week, striking train drivers brought the national rail system to a near-standstill for five days. Wage negotiations in public transport are currently taking place in nearly al…