The passenger who was forcibly removed from a United Airlines flight plans to file a lawsuit, his lawyers say.

Thomas Demetrio, a partner at Corboy & Demetrio and the lawyer representing David Dao, says they plan to file a lawsuit against the carrier and the City of Chicago following the incident onboard an aircraft at Chicago O'Hare International airport on 9 April.

"We're not ready to sue, we're doing our due diligence," he says.

On 12 April, the firm filed an expedited discovery motion with the Cook County Circuit Court in Illinois to preserve all documents and records related to the decision to remove Dao from the United flight.

A hearing for the discovery motion is scheduled for 17 April, says Demetrio.

Dao suffered a concussion, broken nose and lost two front teeth when security personnel for the Chicago Aviation Department forcibly removed him from United flight 3411 bound for Louisville, he says.

"If you're going to eject a passenger, under no circumstances can it be done with unreasonable force or violence," says Demetrio.

The lawyer hopes that the suit will help return some dignity for passengers to flying, he says.

United chief executive Oscar Munoz apologised and took responsibility for the incident in an interview with ABC News on 12 April.

"That is not who our family at United is," he said. "This can never, will never happen again on a United Airlines flight."

Source: Cirium Dashboard