An American Airlines employee has been suspended after allegedly hitting a mother with a pushchair.
A video shot in the aftermath shows a heated argument involving crew, several passengers and a crying woman holding a baby.
The person who recorded the footage, Surain Adyanthaya, claimed it all started when a flight attendant snatched a pushchair from the mother - hitting her and narrowly missing the child.
In the clip shot afterwards, the emotional woman is heard asking for the pushchair back, and a male passenger walks towards the front of the plane and demands the name of the employee who had taken it from her.
Moments later, the man confronts a flight attendant and says: "You do that to me and I'll knock you flat."
An argument then ensues.
American Airlines says it is investigating Friday's altercation, which happened on Flight 591 in San Francisco just before the plane took off for Dallas.
In a statement, the company said: "We are deeply sorry for the pain we have caused this passenger and her family and to any other customers affected by the incident.
"The actions of our team member captured here do not appear to reflect patience or empathy, two values necessary for customer care. In short, we are disappointed by these actions."
American Airlines said the woman and her family have been upgraded to first class for the remainder of their trip.
The company's swift response to the video came after United Airlines suffered a PR disaster when David Dao was dragged from one of their planes by security guards.
Video showed the 69-year-old doctor bloodied and screaming following the incident. He required hospital treatment.
United's initial response to the video was to blame the passenger and describe him as "disruptive and belligerent" - causing international outrage and forcing the company to make an embarrassing U-turn after its share price tumbled.
The furore has meant United's chief executive, Oscar Munoz, has lost out on a promotion to chairman .