United Airlines found itself in the middle of a social media storm on Monday, after the US carrier forcefully removed a passenger from a flight due to overbooking.
The airline said it had asked for volunteers to give up their seats on a Sunday flight bound for Louisville, Kentucky, from Chicago. Police were called after one passenger refused to leave the plane.
Smartphone video posted online showed three Chicago Department of Aviation police officers struggling with a seated middle-aged man.
The man starts to scream as he is dragged off while other passengers look on -- some recording the event with their phones.
One passenger can be heard yelling, "Oh my God, look at what you did to him!"
The incident ignited social media outrage, with "United" a trending term on Twitter, Facebook and Google.
It was another example of bad press and negative social media coverage for the airline, after an incident in late March when two teenage girls were denied boarding a flight in Denver because they wore leggings.
The airline defended its action, saying the girls were flying on passes that require them to abide by a dress code in return for free or discounted travel.
Tyler Bridges, who posted video of Sunday's incident on Twitter, wrote: "not a good way to treat a Doctor trying to get to work because they overbooked."
He described passenger reaction on the plane as "disturbed."
"Kids were crying," he said.
Bridges also wrote that the man appeared bloodied by his encounter with law enforcement and posted video showing him later running back on the plane, repeatedly saying, "I have to go home."
The man appeared to be pacing and disoriented.
United Airlines did not immediately return AFP's request for comment. The company told US media that it had asked for volunteers to leave the overbooked plane.
"One customer refused to leave the aircraft voluntarily and law enforcement was asked to come to the gate," United spokesman Charlie Hobart was quoted by the Chicago Tribune newspaper as saying.
"We apologize for the overbook situation."
US airlines are allowed to involuntarily bump passengers off overbooked flights, with compensation, if enough volunteers cannot be found, according to the US Department of Transportation.