A United Airlines flight from Newark to Denver was diverted following a fight over a device called a "Knee Defender."
The flight had to land in Chicago on Sunday instead.
According to authorities, the fight started after the man set up his "Knee Defender" to prevent the person in front of him from reclining their seat so he could use his laptop.
He refused to remove the device after being asked by the flight attendant, and the woman in front of him responded by tossing a cup of water on him, Denver TV station KUSA reported.
The pair was dropped off at Chicago's O'Hare International Airport. The flight then continued on to Denver.
Ironically, the passengers had been seated in the Economy Plus section, which allows for more leg room.