The Lufthansa subsidiary, Discover Airlines, was forced to cancel a number of flights on Tuesday as its pilots and cabin crew began a four-day strike. A handful of flights were affected, including two long-haul departures and two return flights on shorter routes, a Discover spokeswoman said. Discover operates 27 aircraft from Munich and Frankfurt to various holiday destinations in Europe and overseas. The airline is facing days of disruption after the VC pilots’ union and the UFO cabin crew union launched a strike to protest a collective agreement that rival verdi union reached with management…