Watch: Daughter, attorneys of dragged United Airlines passenger speak out

Crystal Pepper, the daughter of David Dao, a Kentucky physician who was recorded being dragged screaming from his seat on a commercial flight at Chicago's O'Hare Airport described what it was like for her family to see the disturbing videos that have sparked social media outrage.

At a news conference alongside her father's attorneys, Thursday Pepper said, "We were horrified and shocked and sickened to learn what had happened to him and to see what had happened to him."

United later apologized and promised to refund fares to all Flight 3411 passengers, but only after the airline received intense criticism and its stock price plunged. Dao's attorneys filed an emergency motion requesting information be saved for future use, and said a lawsuit will be filed at some point.