Severe turbulence during a United Airlines flight from Denver, Colorado to Billings, Montana sent five people to hospitals in on Monday, an airline official said. Three crew members and two passengers were injured, United spokesman Luke Punzenberger told the Denver Post newspaper. The captain of the Boeing 737 declared a medical emergency as the flight approached Billings, Federal Aviation Administration (FAA) spokesman Ian Gregor told the Billings Gazette newspaper. One flight attendant remained in the hospital late Monday, Punzenberger said, adding that 114 passengers and five crew members were aboard the flight.