United Airlines share prices took a hit early Tuesday, plunging 4 percent amid fierce backlash over its treatment of a passenger who was physically dragged off an overbooked flight. On Monday, after word of the incident spread online, shares of United Continental actually rose by nearly 1 percent. The passenger was identified as 69-year-old David Dao, a doctor and a father of five. Videos from inside the plane showed officials dragging him down the aisle, his face bloodied. United CEO Oscar Munoz apologized in a letter but added that Dao was being “disruptive and belligerent,” despite videos suggesting an apparent overreaction by the airline.