Passenger dragged off United flight will file lawsuit against airline

David Dao's removal was filmed in viral video
Posted at 11:30 AM, Apr 13, 2017
and last updated 2017-04-13 11:33:34-04

(CNN) -- Dr. David Dao, the passenger forcefully removed from a United Airlines flight earlier this week, has filed a lawsuit against the airline, according to a filing listed on the Cook County Clerk of Circuit Court website.

At a press conference on Thursday, Dao's attorney Thomas Demetrio said he believes airlines "bully" their customers.

At the same press conference, Dao's daughter said her family was "completely horrified and shocked" upon seeing video of her father being violently dragged off of the airplane.