A passenger who was branded a "potential time bomb" was offloaded from a transatlantic flight in northern Ireland after he changed his clothes three times and allegedly told an air stewardess that he could 'have all the f****** peanuts' he wanted.

A flight attendant claimed Jeremiah Mathis Thede pointed his finger at her face and demanded to know her name when she refused his request for additional snacks on the flight which was diverted last year.

Lisa Hall told Thede's trial: "He became very angry and he told me he could have all the f***ing peanuts and crackers he wanted."

The United Airlines flight from Rome to Chicago diverted to Belfast International Airport after the alleged air rage incident last June.

United flight attendant Ms Hall gave her version of the in-flight encounter with U.S. citizen Thede as she gave evidence at Antrim Crown Court.

She claimed Thede had come back to the galley area of the economy section a short time after take-off, when the seat belt sign was on, and asked for peanuts and crackers. He was given the snacks on that occasion but when he returned a short time later, Ms Hall said she told him there was only one snack per passenger.

Ms Hall claimed Thede became enraged and pointed his finger at her face.

"I felt like my heart was pounding, that something wasn't right with him," she said.

She added: "He started shouting at me before I could even finish my sentence."

Asked to characterise his demeanour, Ms Hall said: "He seemed extremely angry and it was just not normal behaviour."

The flight attendant with almost 30 years of experience told the court she expressed concern to the head flight attendant that "somebody was going to get hurt".

Asked who, she added: "Anybody confronting this passenger - any passenger on the aeroplane or any flight attendant."

A barrister representing Thede said his client denied swearing or pointing his finger during the conversation about the peanuts and crackers.

Thede, 42, from Berkeley, California, denies a charge of endangering an aircraft or persons in the aircraft.

The Boeing 777 carrying 264 passengers was flying to the U.S. on June 20 last year when the captain made the decision to touch down at Belfast International Airport after concerns were raised about the behaviour of Thede.

On Friday the court heard that Joseph Oka, a United Airlines relief pilot, said he feared the actions of Thede could have been a distraction for something more sinister.

He told Antrim Crown Court: "I was thinking, can this just be a minor incident? Our training is to treat every incident as not minor."

"This could really be a diversion to take attention away from the front."

Mr Oka, a former U.S. navy pilot with 19 years' experience at United, said he made the unprecedented recommendation to "offload" Thede as the plane approached the end of UK airspace.

To the forefront of his mind was an extreme incident where a passenger on a previous flight had been involved in a prolonged struggle before the plane could land, he said.

Oka added: "There could potentially be a time bomb on board. Do you want to deal with it on the ground or in the air, given that we were about to coast out?"

"There would be a long period for someone to get hurt while trying to get to an airport."

The relief pilot, who is legally required to sleep during the first three hours of the flight, described being woken twice and asked to deal with Thede, something that he claims "never happens."

Complaints included allegedly "staring" at a female passenger and invading her personal space.

Thede, who had changed his clothes a number of times and was standing up rummaging through his bag in the overhead bin, had been given three warnings to change his conduct, the court was told.

Mr Oka did not witness any inappropriate behaviour but said he believed the accounts of the crew and concerned passengers.

He said: "Another part of our training is that if any passenger's behaviour or conduct affects the safety or comfort of another passenger, they may be removed - and that was clearly happening."

"I just felt that the crew members" duties had been interfered with enough, we were reaching the point there we were coasting out and once you are over the Atlantic there are not a lot of places to land.

"It's better to offload this gentleman and continue with this flight."

The court heard there was no evidence that Thede's actions were part of a wider distraction plot and shortly after the captain announced the plane was being diverted he appeared to be asleep.

He was only woken when police officers escorted him off, it was claimed.

It also emerged that although restraints were available they were not deployed.

The plane had to dump thousands of litres of fuel before making the unscheduled stop in Northern Ireland.

As the crew would have exceeded their legal flying hours if the aircraft had resumed the journey straight away, the passengers had to wait almost 24 hours before the plane could take off again, with many having to sleep on the terminal floor.

Thede, dressed in a light grey suit and white shirt, listened from the dock as Ms Hall gave evidence.

The trial continues.