RYANAIR "EXPRESSED its concern" yesterday about Aer Lingus's half-year results and called for it to review its strategy.

The Michael O'Leary-led airline was reacting to figures published on Thursday that showed Aer Lingus had a loss of €20.2 million in the first half of 2008.

Ryanair is Aer Lingus's biggest shareholder, owning more than 29 per cent of its rival. Ryanair called on Aer Lingus to scrap its fuel surcharges and described its new Belfast base as an "abject failure".

Ryanair published figures from the Civil Aviation Authority (CAA) for the period January to June this year, which show that Aer Lingus's total average load factor was just 50 per cent. Its load factor on the controversial Heathrow route was 54 per cent.

"Some of Aer Lingus's Belfast load factors are truly awful, with Paris at 31 per cent, Amsterdam at 36 per cent and Nice a very poor 38 per cent," Ryanair said.

"In all cases it would appear that Aer Lingus's load factor is considerably lower than that of Easyjet or Jet2, its competitors at Belfast International Airport."

The criticisms were rejected by Aer Lingus, which said its performance to date was in line with its projections. Aer Lingus began flying from Belfast last December.

Enda Corneille, Aer Lingus's corporate affairs director, said the airline had achieved load factors of 70 per cent or more on all routes from Belfast in July and August.

"We're precisely where we wanted to be," Mr Corneille said. "We've come from a standing start in Belfast.