The viral video of a bloodied Dr. David Dao being dragged from a United Express flight has created strife between travelers and the airline's employees, a union leader said."These media headlines are pitting passengers against crew," said Sara Nelson, international president of the Association of Flight Attendants-CWA. "Flight attendants are the face of the airline, and they're getting the brunt of it."She said many flight attendants have been treated with disrespect since the Dao incident.