A video posted to Facebook Sunday evening showed what is becoming another public relations nightmare for United Airlines, which is owned by United Continental Holdings.
Dr. David Dao boarded a United flight at Chicago's O'Hare International Airport, headed to Louisville, not knowing he was about to be forced to leave a plane that was overbooked.
A nearly 30-second video clip, posted on social media by a fellow passenger, shows three security officers approaching Dao who was already seated, asking him to give up his spot on the plane. After the doctor refuses, he was eventually dragged by his arms and screaming toward the front of the plane.
A witness to the debacle said passengers were warned at the gate that the flight was overbooked, and United was asking for volunteers to switch flights, with reimbursements included. Nobody spoke up.
According to Audra Bridges, who posted the video to her Facebook page Sunday evening, United management came on board the flight and used a computer to randomly select four passengers who would be removed from that trip.
Dao — one of those four randomly selected — claimed he was a doctor and needed to see his patients at the hospital in the morning, then proceeded to say he would call his lawyers.
After being forcibly ejected by three security officers, Dao was able to get back on the plane, though his face was bloody, and he seemed disoriented, Bridges said. United offered no update to the flight's other passengers, who waited for more than two hours for things to calm down before taking off, she added.
The Chicago Department of Aviation said the incident was "not in accordance with our standard operating procedure." It also said that the dragging of the passenger was "obviously not condoned by the department."
"That officer has been placed on leave effective today pending a thorough review of the situation," the department said in a statement to NBC News.
Later Monday, the U.S. Department of Transportation said it is reviewing the incident. "While it is legal for airlines to [involuntarily] bump passengers from an oversold flight when there are not enough volunteers, it is the airline's responsibility to determine its own fair boarding priorities," the DOT said in a statement.
Earlier, United issued a statement, saying: "Flight 3411 from Chicago to Louisville was overbooked. After our team looked for volunteers, one customer refused to leave the aircraft voluntarily and law enforcement was asked to come to the gate. We apologize for the overbook situation. Further details on the removed customer should be directed to authorities."
"This is an upsetting event to all of us here at United," United's Chief Executive Officer Oscar Munoz later followed up in his own statement. "I apologize for having to re-accommodate these customers. Our team is moving with a sense of urgency to work with the authorities and conduct our own detailed review of what happened."
As it often does, Twitter erupted following the posting of this video, with many individuals voicing their concern over the way the man was treated by United employees.
Just last month, two teenagers wearing leggings were stopped from boarding a United flight.
The teens were flying using free passes for employees or family members, and thus were considered airline representatives, a United spokesman said following the incident. The airline said this is why the teens were told by a gate attendant they could not get on the plane wearing form-fitting pants.
Competitor Delta was quick to chime in on social media after the leggings fiasco.
Watch: United now the brunt of jokes