GENEVA—EasyJet will launch flights in four German markets in January, as it picks up routes formerly served by now-bankrupt Air Berlin. The low-cost carrier will start flying from Berlin to Munich, Dusseldorf, Frankfurt and Stuttgart on Jan. 5. It is also launching services to many European business destinations from Berlin. These include Paris, Rome, Madrid, Helsinki, Milan, Stockholm, Vienna and Zurich. Berlin-Munich will be the highest-frequency route, with 51 weekly roundtrips. ...