United says sorry to passenger dragged off plane and vows to 'make it right'

The boss of United Airlines has apologised and pledged to take "full responsibility" after initially backing staff when a passenger was forcibly removed from a flight.

The company has faced intense scrutiny and seen nearly $1 billion wiped off its share price over their defiant stance after the male flyer was removed with such force that he was apparently knocked out.

CEO Oscar Munoz told US news station ABC on Wednesday that this "will never happen again".

He also announced that he would not be resigning over the incident, adding that it was a "system failure".

It came after Mr Munoz issued his third statement in as many days over the incident, offering his "deepest apologies" and saying it is "never too late to do the right thing".

He pledged a full review of the circumstances, and said: "No one should be mistreated this way".

Mr Munoz's remarks sharply contrast with an earlier email that was leaked to press in which he attempted to pin the blame on the "disruptive and belligerent" passenger.

An initial public statement had also apologised for "having to re-accomodate customers" but has failed to address the violence used to remove the man.

The mishandling of the incident has seen United make headlines internationally while it has also become the butt of jokes and memes online.

However, it may have been the stock market's reaction that finally convinced bosses that they needed to rethink their approach.

Share prices tumbled after the incident. Credit: Google Finance

Horrified fellow flyers had recorded footage as the man was violently removed after he refused to give up his paid seat to make way for a member of the plane's staff on an overbooked flight.

Passenger Jayse D. Ansprach, wrote on Twitter that the passenger had explained he was a doctor needed in hospital the next day - at which point staff "decided to use force" with the help of Aviation Security Officers.

Mr Ansprach added that the doctor ran back onto the plane shortly after with a bloody face, shouting "I need to go home".

One woman can be heard on camera shouting during the incident "What are you doing? No, this is wrong. Look at what you did to him."

Audra D. Bridges, who was also on the plane, said the incident left passengers "shaky" and "disgusted".

After video of the incident went viral, the airline's lukewarm apology also attracted mockery and anger on Twitter.