A strike by Lufthansa ground staff has begun at several German airports, a spokesman for the Verdi trade union in Frankfurt confirmed on Wednesday morning. Frankfurt and Munich airports are to be be the hardest hit. Lufthansa, Germany’s largest airline, has cancelled between 80% and 90% of its approximately 1,000 flights scheduled for Wednesday. The strike is expected to last until 7:10 am (0610 GMT) on Thursday. In addition to Frankfurt and Munich, Verdi has also called on employees at various Lufthansa companies in Hamburg, Berlin and Düsseldorf to take industrial action. According to the co…