BERLIN/FRANKFURT: German airline Lufthansa cancelled hundreds of flights on Friday and warned of more disruption on Saturday after a cabin crew union started a series of walkouts that could become the longest ever strike at the carrier. On the first day of a planned week of protest over failed pension talks, flight attendants were instructed to strike at Frankfurt, Lufthansa’s biggest hub, and Duesseldorf between 1300 and 2200 GMT, affecting about 37,500 passengers. That will be followed by walkouts on short-haul flights from Frankfurt and all flights from Duesseldorf between 0500 GMT and 2200 GMT on Saturday, the UFO union announced. According to Lufthansa, that will result in about 520 short-haul flights being cancelled that day, affecting 58,000 passengers. For Friday, Lufthansa said it had cancelled 290 planned flights including 15 long-haul departures, which are typically more profitable for carriers. Eight long-haul flights will still take off, it said.