A runway extension at Belfast City Airport is still necessary despite the launch of a range of European routes using the current one, the chief executive has insisted.
One of the main arguments for the £8 million, 600-metre lengthening was that it would open up the east Belfast facility to holiday destinations on the continent by enabling planes with heavier payloads to take off and land.
But bmibaby's announcement that it will use the current runway to operate new routes to mainland Europe has prompted questions about the need for the extension and renewed calls for the plan to be ditched.
The budget operator said it will be able to do this by changing the thrust setting of the engines on its Boeing 737 300 aircraft. The long-delayed planning application for the extension, first lodged in November 2008, is to go to a public inquiry.
Airport chief executive Brian Ambrose said it still made good business sense to push ahead with the plans. Acknowledging that other operators may also be able to alter their engine thrusts, he said some airlines would still not commit to the airport unless the extension was given the go-ahead.
Last year, Ryanair boss Michael O'Leary was heavily critical of the planning hold up as he withdrew his planes from the airport in frustration.
Mr Ambrose said: "Other airlines want to expand out of this base but are unable to, so the runway extension means we will have less airlines walking away and deals being lost because of runway length."
The application has been fiercely opposed by residents' groups in the east Belfast area, which claim noise levels will soar.
Independent Assembly candidate for east Belfast Dawn Purvis, who expressed concern at the introduction of the new bmibaby routes, said the announcement had also placed a major question mark over the extension.
She said: "I would call on the owners of Belfast City Airport to withdraw their unpopular plans to extend the runway, a plan that is causing such distress to those living in the shadow of the airport and that will bring with it more planes flying lower to homes, further impacting on the quality of life for people living in east Belfast."