Associated PressDENVER — United Airlines says a flight from Washington, D.C. to Denver on Monday was delayed nearly three hours by a "security issue." Airline spokeswoman Mary Ryan declined give Denver's KMGH-TV (http://bit.ly/1zbgEw0) any more details about what delayed the departure of flight 1609 from Reagan National Airport. She referred additional questions to the FBI. Passengers told the station that they were stuck on the plane for 90 minutes after being told the air conditioning needed to be fixed.