MADRID—Police in Spain arrested 12 people and were looking for 12 more after a group of passengers fled a plane onto the runway at Palma de Mallorca airport on Friday night, causing the closure of the airport for several hours. The Air Arabia Maroc flight from Casablanca to Istanbul made an emergency landing at Palma de Mallorca airport after reports of an ill passenger, Guardia Civil said. When the doors were opened at around 8.30 p.m., a group of 21 passengers ran from the plane, the regional government said on Saturday. The events were “unprecedented” in Spain, regional government spokeswoman Aina Calvo told reporters. The 12 arrested included the ill passenger, who was taken to hospital with a companion and given the all clear. The companion then tried to flee the hospital and was also arrested. Another passenger had been arrested for aggressive behavior on board the plane. Calvo said …