Ryanair must pay Aer Rianta more than £350,000, plus interest, for unpaid landing charges and passenger fees, the High Court ruled yesterday.
Aer Rianta, which owns Dublin Airport, had sued Ryanair for £459,885 plus interest, but an earlier court hearing was told Ryanair had paid £103,108 for fees due on the Dublin-Bristol route.
Yesterday's decision by Mr Justice Kelly concerned unpaid fees for 1997 and 1998 on the Dublin-Paris and Dublin-Brussels routes.
In a reserved judgment, Mr Justice Kelly said Aer Rianta had operated discount schemes at sometimes very large discounts of 90 per cent and 100 per cent.
The terms of the schemes were notified to all scheduled customers of Aer Rianta, which claimed no variations were possible.
Ryanair's chief executive, Mr Michael O'Leary, had claimed he had discussions with Mr Brian J. Byrne, Aer Rianta's assistant chief executive, which had resulted in either a variation of the discount scheme for the benefit of Ryanair or a contract which gave advantages to Ryanair.
But, Mr Justice Kelly said, in his view there was no written agreement, and correspondence had demonstrated there was no such evidence of a variation. Aer Rianta had denied the variations, saying they would have required the approval of its board.
What was being said by Ryanair was not credible and was undermined by the very documents exhibited by Mr O'Leary in purported support of his assertions, Mr Justice Kelly said.
The judge refused Ryanair leave to defend the claim against it and gave judgment for £356,777 plus interest at 8 per cent and costs. He refused a stay on his order.