The incident occurred at around 6am Central Standard Time while the plane was landing at Chicago's O'Hare Airport when a woman stood up while holding a child in the aisle of the plane, refusing to sit down as the plane was descending.
In a video of the altercation posted on Twitter, the passenger can be seen becoming irate and screaming "where is it?" at the flight attendant.
The clip, which was captured by fellow passenger Peter Kondelis, then showed the flight attendant attempting to get the passenger back to her seat as she said in a panicked tone: "Ma'am we're landing".
When the woman still didn't sit down the flight attendant could be heard using a more urgent tone as she repeatedly told the passenger "step back".
A second flight attendant could be seen running down the aisle to assist her colleague before the video ended.
The angry passenger could also be heard telling the flight attendant "I will kill you" in a second video posted to TikTok by another passenger, Emily Jean.
Explaining what happened in a follow up video posted to her account, Emily said: "Earlier in the flight she was yelling some gibberish, things no one could really understand and that Jesus Christ our saviour was going to save us, I don't know. But she stayed in her seat."
She revealed that things escalated when the woman decided to head towards the bathroom with her baby while the flight was landing.
Emily said that the woman "started pushing the flight attendant" and also added that she was not drunk. However, she had been accusing another passenger, saying that he "smelled of alcohol".
Police responded to reports of a "disturbance" on United Flight 476 and escorted the woman from the plane after landing.
Three people on the plane, including the flight attendant, were taken to the nearby Resurrection Hospital for observation, according to a statement from the Chicago police department.
They also said that the incident is under investigation by the police and FBI.
This article originally appeared on The Mirror