Brit, 30, who threatened to 'mess up' United plane on flight from London to NYC before being tackled by fellow passengers in air-rage rampage that prompted emergency landing is fined $20,000 NYC

A British tourist who had to be tackled by fellow passengers during a United Airlines flight to New York City after a furious row with his girlfriend has been fined $20,000 in a US court.

Raging Alexander MacDonald, a 30-year-old from Chelmsford in Essex, threatened to 'mess up' the plane during the flight from Heathrow to Newark before he was grappled to the floor and cuffed by passengers and crew.

In March, MailOnline revealed that it was a hero Brit who tackled MacDonald passenger to the ground and cuffed him after he started fighting with his sobbing partner.

The pilot was forced to make an emergency landing in Bangor, Maine when the rampage unfolded on March 1 this year.

Video shot from inside the plane showed the suspect being yelled at by United Airlines' crewmembers who tell him that he has been recorded threatening people on board. 

MacDonald is shown with restraints on his arms and legs with his phone in his hand. A woman begs with him to return to his seat as he slurs his words and attempts to plead his case. 

The clip then cuts to Bangor police officers walking through the aisle, and dragging a restrained MacDonald into custody as the rest of those on board begin to raucously cheer. 

Border police apprehending the drunken man on the plane

Authorities said that he refused requests to calm down during his tirade which prompted the landing in Bangor International Airport.

MacDonald spent three weeks in police custody until he finally admitted to the charges. District Judge Lance Walker said this week that the suspect would not be required to go back to prison after issuing the fine. 

The US Attorney's Office said that the altercation began with MacDonald arguing with his girlfriend, who was traveling with him.  

'When flight attendants asked MacDonald to be quiet and attempted to calm him, he became belligerent, threatening and intimidating towards them,' the Federal Aviation Administration said in a statement. 

At one point, MacDonald said that he would 'mess up the plane,' the complaint said. He was restrained and the flight quickly diverted. Bangor is about an hour's flight from Newark. There were 160 people on board at the time. 

The case was investigated by the FBI, US Customs and Border Protection and the Bangor Police Department. MacDonald and his girlfriend have been banned from traveling with United Airlines.  All but $100 of the fine will be paid to United Airlines, authorities said.  .

Passenger Bobby Field managed to tackle the man to the ground twice on the journey. 

He was later carried off the plane by border police in front of cheering passengers.

Bobby, 38, was traveling to Newark, New Jersey, with his partner Rebecca Guestford. 

The trip was a present for her 31st birthday and it was Bobby's first visit to New York.

But on the last part of the flight on Friday things descended into chaos. 

Bobby, from Brierley Hill in the West Midlands, told BlackCountryLive that they were seated around the center of the plane on the left. 

He said that they had noticed the couple when they boarded. 

Bobby said: 'It was about six hours in when the lad started getting a bit rowdy and you could tell he had been drinking. He started grabbing her jacket and throwing stuff about.'

He said the girl was so upset that she moved and was seen crying.

The air stewardess came over to speak to her and she stood up and made her way to the back of the plane.

But then things got out of hand again.  

Bobby said: 'He got out of his chair and followed them and you could tell words were being said - it was getting heated.'

He said that the man involved was a 'big guy' and he was ready to help if needed.

'It was getting louder and louder and you could tell that something was going on and next thing was the air stewardess came running out and grabbed me on the shoulder,' he said.

'She asked if I could help, so I got up and walked into the back.

Bobby, 38, was travelling to Newark, New Jersey, with his partner Rebecca Guestford. Pictured: Bobby and Rebecca in NYC

'I just approached him and said, "Look mate, calm down. We're in the air and people are getting upset just come and sit down."'

Bobby said the man turned around and came at him so he 'flipped him over and put him on the floor' so that he was on his front with his hands behind his back.

An American man helped them and they put cuffs on the passenger's hands and legs.

Bobby said he was shouting and they kept him in that position, telling him to be calm.

He said the girl had become hysterical and they left the man for a few minutes to unwind. 

They put a pillow under his head and gave him some water but he didn't want to stop. 

Bobby, who works on the roads, said that every time the man spotted him, he started shouting again.

He told him that if he calmed down then he would be allowed to get up, so they stood him to his feet. 

But he continued shouting, so he was placed in a chair at the back of the plane.

Bobby said he stayed out of his way because he was the one that had angered him. 

He said that every time the man spotted him, it set him off and he wanted to go for him. 

The border police carried the man off the plane in Maine in front of cheering passengers after the flight was diverted

So Bobby kept out of his way, hoping that it would bring the situation to a close. 

They stood up and he was shouting, so he asked his girlfriend to pass him his phone and he began recording them, saying 'you've assaulted me'.

Bobby said that it was pointless trying to talk to him because he was drunk and after around 20 minutes he was taken away again.

Bobby's girlfriend filmed part of the row at the back of the plane. 

He was told that as they were still an hour and a half from their destination if the man calmed down then the flight could continue. 

But the passenger kept mouthing off, so the captain made the decision to divert the flight. 

Ten minutes later, they arrived in Maine and within seconds the border police had seized him by his hands and legs and carried him off the plane. 

Bobby said they were there for around an hour. He gave a statement to the police and then someone from the FBI came to chat to him. 

He said the plane refueled and they set off again to New York.

Bobby said that everyone cheered and clapped when he exited the plane and lots of people shook his hand. 

Despite his impressive intervention, Bobby does not consider himself a hero and the altercation did not spoil the couple's trip. 

They even bumped into a few of the passengers in New York who wanted to thank him.