Police say a passenger's dispute over wanting more nuts was behind a Chicago-bound United Airlines flight being forced to divert to Northern Ireland.

The flight from Rome made an unscheduled landing in Belfast on Saturday.

Jeremiah Mathis Thede, a 42-year-old with dual Italian and American nationality, was charged with endangering the safety of an aircraft, disruptive behavior and common assault.

Police told Coleraine Magistrates' Court on Monday that the trouble began soon after takeoff when Thede demanded "nuts or crackers."

He was given some nuts but later asked for more, and the situation escalated until the pilot became concerned about Thede's erratic behavior.

Thede's lawyer said his client denies wrongdoing.

Many of the 282 passengers spent the night at Belfast airport before flying on to Chicago on Sunday.