BILLINGS, Mont. -- The Yellowstone County Sheriff's Office says a woman passed out on a commercial flight from Chicago to San Francisco and the plane made an emergency landing at the Billings Logan International Airport on Saturday night.A sheriff's department dispatcher says the woman was later pronounced dead. An autopsy is scheduled to determine the cause of death, but authorities say she had medical issues. The woman was not identified.According to the Billings Gazette , the flight was a Star Alliance Boeing 737 that left Chicago about 7 p.m.