CHICAGO (AP) — Video of police officers dragging a passenger from an overbooked United Airlines flight sparked an uproar Monday on social media, but United’s CEO defended his employees, saying they followed proper procedures and had no choice but to call authorities and remove the man.As the flight waited to depart from Chicago’s O’Hare Airport, officers could be seen grabbing the screaming man from a window seat, pulling him across the armrest and dragging him down the aisle by his arms. United was trying to make room for four employees of a partner airline on the Sunday evening flight to Louisville, Kentucky.Other passengers on Sunday night’s United Express Flight 3411 are heard saying, “Please, my God,” ‘’What are you doing?” ‘’This is wrong,” ‘’Look at what you did to him” and “Busted his lip.”Passenger Audra D. Bridges posted the video on Facebook. Her husband, Tyler Bridges, said United offered $400 and then $800 vouchers and a hotel stay for volunteers to give up their seats.