Several passengers and flight attendants were injured Monday during a bumpy flight from Denver to Billings.
United Airlines Flight 1676 ran into turbulence while descending into Billings, said United spokeswoman Christen David.
"The flight encountered severe turbulence upon descent into Billings, Montana," she wrote in a news release. "Three crew members and a number of passengers were injured."
United Airlines spokesman Luke Punzenberger told The Denver Post that three crew members and two passengers were injured Monday.
Ian Gregor, Federal Aviation Administration spokesman, said that the flight's captain called a medical emergency as the plane, a Boeing 737, approached Billings.
"The plane landed in Billings without incident," Gregor said in an email.
He referred further questions to United.
One flight attendant remained in the hospital late Monday, Punzenberger said. He said 114 passengers and five crew members were aboard.
Passenger Joe Frank, 20, told The Denver Post in an email that the plane dropped violently and he heard a loud bang. He said a baby was propelled out of a parent's arms and landed in a seat nearby, but the infant didn't appear to be hurt.
"I didn't have my seat belt on, so I hit my head pretty hard but what hurts is my lower back and hips," he told the newspaper. He said he was heading from a visit to Texas back home to Billings.
Emergency crews and the Billings airport fire department responded.
Information about the attendants' and passengers' injuries wasn't available and David said United will also investigate the incident.
"Our primary focus is assisting our employees and passengers who were injured, and our flight safety team will review what happened," she said.
Billings Logan International Airport officials weren't available for comment.
According to United, Flight 1676 left Denver International Airport just before noon and landed in Billings shortly before 1:30 p.m.
The Associated Press contributed to this story.