BERLIN (Reuters) -Pilots at German flagship carrier Lufthansa voted on Sunday by a margin of 97.6% in favour of industrial action, threatening further disruption during the busy summer travel season. Strikes and staff shortages have already forced airlines including Lufthansa to cancel thousands of flights and caused hours-long queues at major airports, frustrating holidaymakers keen to travel after COVID-19 lockdowns. The vote does not necessarily mean a strike will be held, but it was a signal to the employer that constructive steps needed to be taken, pilot’s union Vereinigung Cockpit (VC) …