However, Russell Payne, 52, is serving the time in lieu of paying fines totalling £500 for the offence, which he had denied.
Payne had argued that there were no signs on the fences that he had climbed but Judge Marc Davies said the law required only that there be sufficient signage that people were aware that it was a restricted area.
The law allowed only for a fine to be imposed for a breach.
Payne had previously told the court that he was not on benefits, had no savings and lived off welfare handouts.
In light of this, and the fact that he had been in custody for about four months, the judge said he was prepared to impose smaller fines of £250 for each offence.
Payne was given six months to pay the total of £500 or face 25 days in prison in default, but he chose to serve the prison time.
He was also found guilty of assaulting an airport firefighter by throwing water at him and sentenced to two months in prison, suspended for six months.
He had also denied resisting police officers in the due execution of their duty but was also found guilty of this offence and sentenced to two weeks in prison, to run concurrently.
On the second occasion he had been found within the airport perimeter wearing only a T-shirt. He had earlier been seen in a private garden by the woman who lived there.
He denied indecency, though Judge Davies found this proven, but made no separate order. He said that there was no proof that Payne had deliberately sought to upset anyone and so found him not guilty of a charge of indecent exposure.
Prior to sentencing, Judge Davis praised the airport firefighters, security officers and police officers for their evidence which he said he had found clear and credible.
By contrast, he had found Payne’s testimony to be confused and confusing at times, although he had been clear about his description of his defence, which revolved around the lack of signage.
Airport invader said he intended to go on night-time jogs
PLANS to go for night-time runs were what led Russell Payne to climb over fences into the airport grounds, he told the Magistrate’s Court.
Payne represented himself at trial and chose to give evidence.
After taking the stand he said on the first occasion he had gone out at about 11pm from the house near the airport where he had been living.
Payne had heard of an old school field nearby and was going to run there. He had thought about running in the Specsavers car park, but did not want to aggravate a medical condition by running on hard ground, and so he said he walked through the car park towards what he thought was an old school field.
There was a fence, which he took to be the Specsavers boundary fence, since there was no sign on it indicating otherwise, and he climbed over it.
Soon after this he was spotted by a member of the airport staff and, after being directed to the terminal building, he was arrested and taken to the police station.
Crown Advocate Fiona Russell, prosecuting, put it to him that the time had actually been about 5am, not long before the airport opened, but Payne said it was pitch dark and he had assumed it to be about 11.
After being released from custody he had walked back to his friend’s house where he had ‘pottered around’ for a while.
He said he later decided to try going for a run again, and found a pair of black running shorts which he said he thought he had put on underneath his tracksuit bottoms.
Before leaving, he decided to take with him a small box containing jewellery belonging to his mother, since he was concerned that the other man in the house might wander into his room and take it.
He left the house at about 5.30am and walked in the opposite direction to the previous day, going down to the bottom of the cul de sac where he saw a low fence.
He said he could not see any signs on it, so made to climb over.
As he did so, he caught his tracksuit bottoms on the fence and, because they were also dirty, he climbed down, took them off and then climbed over again, intending to run in his T-shirt and shorts.
It was only when he was challenged by an airport staff member that he realised he was not wearing the shorts. He said he was suffering from extreme sleep deprivation, having had only about half an hour in the previous few days, which he said could have explained why he had not realised he did not have the shorts on.
Other people arrived, including one who gave Payne a bottle of water, which it was alleged he threw over an airport firefighter, as well as striking out at him.
Payne said that he had dropped the water after being grabbed, and denied throwing it at the man.
Crown Advocate Russell put it to Payne that he had deliberately gone onto the airport land and had exposed himself in order to insult the people at the airfield, but he denied both claims.