Celtic Helicopters borrowed £185,000 from Mr Ben Dunne in 1991 to buy land near Dublin Airport, the Moriarty Tribunal was told yesterday.
Mr Dunne confirmed that he made the money available after an approach by one of the directors of Celtic Helicopters, Mr John Barnicle.
The land was subsequently bought and the loan was repaid in full, he added.
Asked by the tribunal chairman, Mr Justice Moriarty, if the transaction had been "commercial", Mr Dunne said: "To be honest, if I hadn't known John Barnicle from flying me around the country all the time, he'd never have got the loan."
His only concern had been securing his "capital", he added.
"My solicitors said I got interest. I don't know. I wasn't looking for it."
However, he said he accepted the word of counsel for Mr Barnicle, who said it would be her client's evidence that interest was paid.
Mr Dunne also told the tribunal that only himself or company trustee Mr Noel Fox could have handled the so-called "bearer cheques" totalling some £32,200 which found their way into a bank account for the benefit of former taoiseach Mr Charles Haughey in 1987.
He said the cheques - of the sort used by Dunnes Stores for staff bonuses - would have originated with him in either case, because of their size.
But he added that he had no recollection of giving them to Mr Haughey. "If I didn't give them myself, I could have given them to Noel Fox for Mr Haughey," he added.
Counsel for Mr Fox, Mr Maurice Collins, said his client had given evidence "in emphatic terms" that he did not know what had happened to the cheques or how they had made their way into the Guinness and Mahon account: "I take it from your evidence you are not in a position to contradict him?" Mr Dunne agreed he was not.
Counsel for the tribunal, Mr Jerry Healy, referred to earlier evidence in which Mr Dunne spoke of having a "vague recollection" that three grocery account cheques totalling £180,000 had been given by him to Mr Barnicle - a point Mr Barnicle has contradicted.
Asked by Mr Healy if he could be confusing this transaction with the £185,000 loan, Mr Dunne said: "No I remembered this [the loan] clearly."
Asked if his memory of the grocery cheques had improved since he had last given evidence, Mr Dunne told the tribunal he regretted that it had not.
"It's just the vaguest of recollections," he said.
