A video showing a man being violently dragged off an overbooked United Airlines flight on Sunday has led to an uproar on social media.

Just a few weeks after the United Airlines received a backlash for banning two girls wearing leggings, the airline made headlines in both the United States and China after the video was posted online by another passenger.

The footage captures aviation officers forcibly pulling a 69-year-old male from a window seat on flight 3411.

The scene occurred just before the aircraft was about to take off from the Chicago O'Hare International Airport, headed to Louisville.

The man, only known as a doctor, had a bleeding mouth and was mumbling in the video. Cries for help from other passengers could also be heard.

A 69-year-old male who was violently dragged off a United Airlines flight is seen a video clip. [Photo/Twitter]

United Airlines confirmed airline employees were trying to make room for four employees of a partner airline.

According to an unidentifiable witness, the company firstly offered $400 vouchers, which was then increased to $800, and free accommodation at a nearby hotel to passengers willing to give up their seats on the overbooked flight.

After many passengers refused, airline staff automatically picked four passengers to be removed.

The elderly doctor, who had Asian facial features, refused to leave and said he had to work at a hospital the next day.

The US Department of Transportation has already started investigations into the matter.

Since the incident, one of the Chicago Department of Aviation security officers, involved in the scenario, has been placed on paid leave.

The incident has attracted a lot of attention from Chinese media, including People's Daily, which published the video on Sina Weibo.

Attention has since continued to rise on the Chinese social media platform, and the United Airlines situation was rated the most popular topic on Tuesday.

Among the ever increasing comments was Joe Wong, a Chinese American comedian who shot to fame after making appearances on the David Letterman and Ellen Degeneres shows.

Wong called for 2.6 million followers on Weibo to sign a petition for boycotting the airline. Some Weibo users responded, stating they would never fly with the airline again.

The latest incident also prompted reminiscence of bad customer service experiences.

A Weibo user recalled an experience of how staff at the Untied Airlines refused to apologize for misplacing her luggage, which was lost at an airport in Chicago.

"Since the incident, the United Airlines is on my no-fly list," she said.

If the boycott of flights continues, business for the United Airlines could stumble in the Chinese market – a market where the airline has made strides in recent years. Last year the market-savvy carrier added two direct flights to its already busy China-US air routes: Xi'an/Hangzhou-San Francisco.

The airline's move to apologize has since been closely watched by many online users in China.

Oscar Munoz, the CEO of United Airlines' parent company, defended the actions of United Airline staff in a letter to employees, after first writing a statement.

Munoz said he was "upset to see and hear about what happened" at O'Hare.

He then added the man was dragged off the plane because he ignored requests by crew members to leave, and became "disruptive and belligerent".

"Our employees followed established procedures for dealing with situations like this," he said to employees of United Airlines.

"While I deeply regret this situation arose, I also emphatically stand behind all of you."

After the letter went public, online outrage escalated on Weibo and many users cited his response to the incident as having a bad attitude.

At the other side of Pacific, a similar reaction emerged on Twitter, which has been flooded with a mixture of anger and mockery.