Two US army veterans in their 80s have been fined €5,000 each after they were convicted yesterday of interfering with the operation of Shannon Airport by entering a runway during an anti-war protest three years ago. They were acquitted on charges of trespass and criminal damage.

The two men, described by an airport officer as the "nicest, most courteous protesters" ever encountered, had pleaded not guilty to the charges, claiming their actions were justified under international law.

Passing sentence today, Judge Patricia Ryan said she had to mark the seriousness of the offence while taking into account the personal circumstances of the men. She said an aggravating factor in the case was the interference by being on the runway causing its closure. The judge said this was a very serious matter from not only a security perspective, but the danger caused to themselves and others.

Judge Ryan said she was taking into account the fact that the men had been held in custody for almost two weeks after their arrest and were prevented from returning home to the US for nine months as part of their bail conditions.

The maximum sentence for the offence was a fine of €250,000 or two years in jail.

The court was told the men had each lodged €2,500 each as part of their bail and needed more time to raise the remaining €2,500 each.

The case was adjourned for a short time to allow the money to be found. A number of supporters were with the men in court.

The judge said the men had been apprehended for their own safety. She said the mitigating factors were that they had no previous convictions, had made admissions at the trial and were cooperative and courteous.

She also took into account their previous good character and excellent work record, and the reasons they gave for their actions, adding: "But it is a criminal offence and a serious charge which puts people at risk.

"Happily, others were not put at risk at that time so I am not taking that into account as an aggravating factor."

Earlier, prosecuting counsel Tony Magillicuddy told the court that the men's presence on the airfield that day caused it to close for 40 minutes. He said the airport duty manager had asked the men if anyone else had accessed the airfield and got "a political narrative about neutrality ".

As the integrity of the airfield could not be ascertained, it was forced to close.

During the 40-minute closure, one aircraft had to engage in a holding pattern that added 30 minutes to the flight, costing €4,300 in extra fuel.

Three other aircraft had their departure delayed, including a Ryanair and an Aer Lingus flight.

Defence counsel Michael Hourigan for Mr Mayers had earlier asked the judge to take account of his client's circumstances and the fact that he had cooperated with the case.

He said Mr Mayers had joined the US military at a very young age and served for 20 years, obtaining the rank of Major.

Since leaving the military he held a variety of roles and had secured a doctorate from the University of California. He asked the court to take into account his circumstances, his work record and the way he had dealt with the matter in a courteous and respectful way throughout.

Counsel for Mr Kauf, Carol Doherty, said her client had already been deprived of his liberty serving 13 days in prison after his arrest and having to stay in Ireland for nine months as part of his bail conditions. She said her client had outlined his motivation for his actions during the trial.

Ken Mayers, 85, and 80-year-old Tarak Kauff, who have addresses in the United States, walked on to a taxiway at the airport on St Patrick's Day 2019, wearing high-vis vests bearing the words 'Veterans for Peace’. They said they intended to inspect a plane used to transport US military personnel and were protesting against the use by the United States of Shannon as a stopover enroute to areas such as the Middle East. The runway had to close for a period of time and a plane which was due to land could not do so while the runway was closed.

Yesterday the jury found them guilty on a single charge each by 10:2 majority verdicts.

The trial heard that Ken Mayers, from Santa Fe in New Mexico, and Tarak Kauff, of Woodstock in New York, both served in the United States Military before becoming antiwar activists in the 1960s.

The prosecution said that on the morning of 17 March, 2019, the men cut through the perimeter fence at Shannon Airport. Gloves and bolt cutters were later found inside the grounds. Airport personnel saw two men in high vis jackets on a taxiway in the airport, one of them carrying an Irish flag.

The men admitted being involved in making an opening in the fence and entering the airport lands, but they each pleaded not guilty to criminal damage, trespass and interfering with the operation, safety or management of an airport. The damage to the fence was valued at €590.

When they were stopped by a fire officer, the men told him they were peace protesters and were going to check an American aircraft. Richard Moloney said they were the nicest and most courteous protesters he had ever met in his 19 years at Shannon Airport.

He said they were wearing high-vis vests with the words "Veterans for Peace" and one of them was holding a document with a picture of an Omni Air aircraft on it. The court was told this was a civilian airline which also transports American military personnel and on the day in question, an aircraft that had transported US military was awaiting maintenance on the airfield. The court heard the men intended to inspect the plane and were holding a folded banner saying ‘US veterans say respect Irish neutrality, American war machine out of Shannon Airport’.

The airport was shut down for 30 to 40 minutes after they were discovered.

The men were arrested and Mr Mayers spent 13 days in Limerick Prison after initially being refused bail. The member in charge at Shannon Station said the two men were the "best custodians he had in 25 years".

In their evidence at Dublin Circuit Criminal Court, the men said their actions were legal under international law.

Mr Kauff told prosecuting counsel Tony McGillicuddy that he was acting on his own moral beliefs when he damaged the fence. He said the US and Irish governments had been breaking the law and Irish people were sick and tired of their government cow-towing to the US. He claimed there was a higher purpose than the law which says you can’t trespass or cut a fence.

Mr Kauff said he had friends who had taken their own lives because of what they had done while in the US military.

He told Mr McGillicuddy, that was the real damage and damaging a fence was nothing.

"Nobody died," he said and told Mr McGillicuddy that he expected he should understand that as well.

Both men alleged the Irish Government was in breach of international law and Ireland’s neutrality by allowing planes contracted to the US military to transition through Shannon Airport.

Mr Mayers said if a belligerent country landed in a neutral country, that country had an obligation under international law to inspect the plane. He said the use of Shannon by the US military was part of the process of killing many, many people and he said what the US government was doing was a great disservice to the Irish people.

He said he and Mr Kauff understood that the Irish people were very conscious of the importance of Irish neutrality.

Mr Mayers said he knew he was making an intervention that would violate a statute, but he said this was to "prevent something worse", and he said he took his action to save lives.

He said they hoped that by entering the airfield they would persuade and encourage airport police and gardaí to inspect the plane. He said at times it was necessary to go beyond the laws of a State to get a point across. He took action in defence of people who were seriously being attacked, he said, and he decided to break the law in order to serve a higher purpose. The authority for his actions, he said, was the obligation to do what is right.

Mr Mayers said he was a habitual peace protester. He said he had never been treated better by law enforcement officials than by the gardaí.

Prosecuting counsel Tony McGillicuddy told the jurors the two men were sincere and honourable people and that could not be disputed.

However, he told them to put sympathy aside and have regard to the law.

He said the jury had to consider if the men had an honestly held belief that their actions were justified to protect other people. He said the prosecution case was that they did not have any such lawful excuse and were there to make a political statement. Any qualms, claims, contentions, worries or concerns should have been reported to the authorities in the proper way, he said.

Mr Mayers’ defence counsel,Michael Hourigan, said it was not some kind of political posturing but an honestly held belief that their actions on the day could save lives.

He told the jurors that although the prosecution had claimed there were no arms on the plane, there was no practice of inspecting US military planes at Shannon.

Mr Hourigan said that when the jurors reach the age of 85, they may be doing something different than standing in the mud in a wet field in Co Clare, but he said that was what Mr Mayers felt he had to do to protect human life and he said there was a lot more to constitutional democracy than the letter of the law.

He urged the jurors to be the lamp and show that freedom lives by delivering verdicts of not guilty.

Mr Kauff’s defence counsel, Carol Doherty, said a person cannot be convicted of criminal damage in Ireland provided they can show they honestly believed their actions were lawful.

She pointed out that no airlines lost any money as a result of the airport closure and the delays were minimal.

She said her client had dedicated his life to peaceful protest.

"People who go against the great can make a difference," she said, adding that it was reasonable to assume the two men might have made a difference.

The fact that their hope was not realised on this occasion did not mean the action was not justified.