An Envoy Air flight returned to Chicago shortly after takeoff on Saturday night after a pilot was incapacitated and later died, the carrier said Tuesday.
Ric Wilson, vice president of Envoy's flight operations, said in a note to staff that the pilot was a captain in training.
The Air Line Pilots Association, the union which represents Envoy's pilots, didn't comment.
Envoy Air Flight 3556, an Embraer E175, flying for parent company American Airlines ' American Eagle returned to Chicago O'Hare International Airport at 7:57 p.m. local time, 37 minutes after departing for Columbus, Ohio, according to FlightRadar24.
"We're going to need paramedics," said the person on the recording, who seemed to be another pilot on the flight.