A United Airlines flight made an emergency landing in Chicago after two passengers got into a fight over reclining seats.
It happened Sunday on a flight from Newark to Denver.
Witnesses say one passenger put a device called a Knee Defender on his tray table to prevent the person in front of him from reclining.
This inexpensive device made headlines earlier this summer but was quickly banned by all major U.S. airlines.
The man said he was trying to work on his computer and refused to remove the device.
He was kicked off the plane, and so was the other passenger, because she threw a cup of water at him.
The flight continued on to Denver a little late, but without further incident.