A California family that was not allowed to board a cross-country flight says they believe they were discriminated against because their son has Down syndrome.Robert Vanderhorst, his wife Joan and 16-year-old son Bede, who is disabled, were booked to fly on an American Airlines flight from Newark to Los Angeles...when the boy and his parents were not allowed on the plane...When the family was ready to board, they were stopped by airline personnel, told their son was a “security risk” and would not be allowed on the flight, he said...American Airlines spokesman Matt Miller said the disabled boy was agitated and running around the gate area prior to boarding, which his parents dispute...[According to the boy's parents] “The problem is this pilot thought my son might not be like most people. He didn’t want a disabled person disturbing other passengers in first class.”