Social media users are viciously attacking United Airlines over the brutal removal of a passenger from an overbooked flight, as well as the airline CEO's claim that the passenger was "re-accommodated," in an incident that left the man dazed and bloody.

The outrage was prompted by videos showing security dragging a passenger from a plane at Chicago's O'Hare International Airport, after wrestling him out of his seat when he refused to leave. United says the man was one of four passengers chosen at random, after no one accepted the airline’s offer of a US$800 voucher for anyone who volunteered to be removed from the overbooked flight. The seats were needed for the aircraft's standby crew.

Witnesses say the passenger refused to leave, explaining that he is a doctor, and needed to reach his destination on time, so he could see patients in the morning.

The drama unfolded on a flight from Chicago to Louisville, Ky., on Sunday, resulting in a three-hour delay in takeoff.

"I apologize for having to re-accommodate these customers," United CEO Oscar Munoz said in a statement. Munoz said he has reached out to the man who was dragged off the flight in order to directly address the situation.

However, he also came out in support of his staff. "While I deeply regret this situation arose, I also emphatically stand behind all of you, and I want to commend you for continuing to go above and beyond to ensure we fly right."

Chicago's aviation department offered a more apologetic statement, saying that it does not condone what happened, and that the security officer who grabbed the passenger has been placed on leave.

Munoz's tone-deaf response to the situation didn't sit right with the public. The link-sharing Reddit community was awash with United-related discussions on Tuesday, including many jokes and links to old stories about the airline.

Online dictionary searches of the term "volunteer" spiked by 1,900 per cent on Monday, according to Merriam Webster.

Meanwhile on Twitter, outrage blended with humour under the hashtag #NewUnitedAirlinesMottos. "Board as a doctor, leave as a patient," several users said.

"Let us re-accommodate you," read another popular poster, which included the United logo streaked in blood.

#NewUnitedAirlinesMottos

Why beat your competitors when you can beat your customers? — Zeldro (@byzeldro) April 11, 2017

Board as doctors, leave as patients #NewUnitedAirlinesMottos — Osama Nadeem (@osamanadeem) April 11, 2017

#newunitedairlinesmottos I was going to book a flight with @united but thn I rememebered my chances of being "voluntarily reaccommodated". — mel (@Melonie_FDN) April 11, 2017

#NewUnitedAirlinesMottos

"We will seat you, beat you, and blame you for our overbookings" — Missy See (@MyNameIsSee) April 11, 2017

Our service will knock you out#NewUnitedAirlinesMottos — Cockatoo Bastard (@Tuigen) April 11, 2017

Ladies and Gentlemen, this is your captain speaking. We have reached the Bruising Altitude.#newunitedairlinesmottos #UnitedAirlines pic.twitter.com/ct1NhQcDH3 — Happening Babua (@HappeningBabua) April 11, 2017

"We're altering our seating arrangements, pray we don't alter them any further" #NewUnitedAirlinesMottos pic.twitter.com/KJ8mPUNTVx — Daniel Oz (@DanielTOzborne) April 11, 2017

#NewUnitedAirlinesMottos

"We will seat you, beat you, and blame you for our overbookings" — Missy See (@MyNameIsSee) April 11, 2017

The outrage spread as far as China, where a video of the incident was viewed more than 190 million times on the country's popular Weibo social media service. Weibo users accused United of bias against Chinese passengers, and called for a boycott of the airline.

The hashtag #BoycottUnited was also trending in North America.

@united @USAnonymous Look at this human being's face. You will NEVER find me on any of your future flights. #boycottunited pic.twitter.com/L36mxEAHSM — Phil (@mtnhill) April 10, 2017

Congrats United, you now have all the volunteers you could ever want giving up their seats on your flights.#BoycottUnited — Bing Leng (@coldice77) April 10, 2017

Don't worry about me EVER buying another ticket for you if that is the best that you can handle your passengers!!! #BoycottUnited — Lindsey S. Edwards (@LindseySEdwards) April 11, 2017

I will never fly #uinited again. Overbooking, assaulting paying customers, clueless CEO blames customer. #boycottunited — Mike C (@BlueMikeNJ) April 11, 2017