A distraught flight attendant disrupted an American Airlines flight Friday with warnings that it was going to crash, references to the September 11, 2001 attacks and a rant on the carrier's bankruptcy reorganization.

Two flight attendants were injured in the incident, which began as the Chicago-bound flight was about to take off from Dallas, Texas.

Passengers ended up restraining the disruptive attendant until airport police arrived.

"We were pretty frightened," said passenger Greg Lozano of Elmhurst, Illinois. "I was glad we weren't in the air. That was the primary thing I was thinking."

The flight attendant continued to scream as she was handcuffed and removed from the plane, passengers said.

"I will never get that sound of her screaming out of my head," said Bethany Christakos of Plano, Texas. "It took a good 10 minutes, it felt like, to get her off of the plane."

The incident began as the flight attendant was giving preflight safety instructions and began speaking incoherently over the public address system, according to passengers debarking in Chicago.

She then said the plane had a mechanical difficulty and was going to return to the gate.

Other flight attendants interrupted her and said there were no problems and that passengers should prepare for takeoff. 

They tried to calm their distraught colleague down, but she began ranting in incomplete sentences about the plane crashing, the bankruptcy and the terrorist attacks.

Some passengers took out their mobile phones and called police.

Others said they thought she was having a mental breakdown, and one heard her say she was bipolar and hasn't been taking her medication.

"Our customers were not in danger at any time," the airline said in a statement.

"We apologize for any inconvenience to our customers, and we appreciate their patience and understanding."

The flight was able to depart just an hour and twenty minutes late after the original crew was replaced. Two flight attendants were taken to a local hospital, an airline spokeswoman said.

"We will ensure that the affected flight attendants receive proper care, and we commend our other crew members for their assistance in quickly getting the aircraft back to the gate so that customers could be re-accommodated," the airline said.

The Federal Aviation Administration confirmed there was an "altercation"

involving American Airlines Flight 2332 but did not provide details.

American Airlines has maintained normal operations after filing for bankruptcy protection on November 29. (AFP)