German airline Lufthansa estimates industrial action by employees has cost the firm €250 million ($272 million) so far this year. In an internal memo to employees on Wednesday, Chief Financial Officer Remco Steenbergen said financial burdens caused by the strikes lasted longer than the industrial action itself and included after-effects on crew rosters, aircraft schedules and customer uncertainty. For example, the otherwise profitable connection between Frankfurt and San Francisco had to be cancelled for an entire week. He said customers are now more reluctant to book, and if they do, they avo…