A policeman from Belfast International Airport Constabulary told the court the trouble began when Mr Thede allegedly stood up 15 minutes after take-off, with the seat belt lights still on, and demanded "nuts or crackers". He told the court the American refused to sit back down again until a member of the flight crew managed to "appease" him by giving him some nuts.
However, 10 minutes later he got up and demanded more. Crew members replied he would only get another snack if there were packets left over when other travellers had been served.
The policeman said Thede retorted: "I can have as much nuts and crackers as I f***** want."
Fellow passengers were also concerned by his behaviour, claiming he kept getting up from his seat, repeatedly opened the overhead baggage lockers, blocked the aisles and made numerous trips to the lavatory.
The captain asked several men to sit around the passenger in case he became violent. The policeman acknowledged that "no one was struck" during the flight.
Mr Thede's "erratic" behaviour prompted the captain to turn round when he was already over the Atlantic, and head back to land at Belfast International Airport.
Asked by a prosecution barrister to assess the cost of the incident, the policeman replied: "It would be upwards of £300,000 to £350,000. There is compensation for passengers. There were 269 passengers lying sleeping on the floor of the terminal."
Mr Thede denies the offences and told police the pilot had overreacted. The policeman said: "He said it wasn't him, there was a conspiracy theory against him, people were picking on him."
Mr Thede's solicitor said alcohol was not a factor, as a police doctor had examined him upon arrest and deemed him "fit to be interviewed".
The defendant was remanded in custody to appear before magistrates next week. The police opposed bail, saying there was a risk he could abscond.
Judge Christopher Holmes also ordered a psychiatric examination.