When plans were approved for Dublin Airport's Terminal 2 in 2007, the overall number of passengers at the airport was capped at 32 million a year.
One of the reasons for this, the Government has said, were concerns over the capacity of the roads and infrastructure around the airport.
Almost 14 years after Terminal 2 began operations, Dublin Airport's operator, daa, wants to increase its passenger numbers from 32 million passengers per year to 40 million.
Ryanair CEO Eddie Wilson told Prime Time that passenger capacity at Dublin Airport should be increased or the Irish economy could miss out.
"It [aviation] supported the economic miracle on this island, and stopping it is going to cost jobs, connectivity in tourism, and that's what's going to happen," Mr Wilson said.
"We have an airport that's artificially constrained by a planning application that wasn't put in on time, and it was on the basis of noise emissions back in 2007," he added.
The expansion of passenger numbers is part of daa’s wider infrastructure plans for Dublin Airport.
Planning permission has been submitted to Fingal County Council for 11 infrastructure projects, including the expansion of the north and south aprons to accommodate extra aircraft and the expansion of the check-in and passenger services area within Terminal 1, which includes the relocation of the existing security area.
An interim cap increase to 35 million passengers has also been suggested by daa, as it awaits a decision on the expansion plans.
Daa says the new infrastructure and passenger cap will bring jobs and millions of euro in economic growth to the Irish economy. However, the plans are causing anger among those already in dispute with the airport over noise and those who say the expansion will increase aviation emissions.
Due to the current cap on passengers, daa says it has had to turn airlines away from Dublin Airport.
"I think this is a key choice for Ireland. If we are turning away airlines because we're saying the cap has to stay, then ultimately we are going to lose jobs, airfares are going to go up," daa CEO Kenny Jacobs told Prime Time.
"The airport standards won't necessarily improve and emissions vitally might actually disimprove."
There is also potential turbulence in Government. Some Green Party TDs have publicly opposed the plans on environmental grounds, but coalition colleagues, including Minister for Finance Michael McGrath and Taoiseach Leo Varadkar, are in favour of the expansion.
Green Party MEP Ciarán Cuffe said with an additional eight million passengers per year, "there's bound to be a significant increase in emissions".
"We've got to tackle the greenhouse gas emissions from aviation. While ostensibly on paper, greenhouse gas emissions are just under 4% of Europe's emissions, if you take into account what are called the non-CO2 effects, the soot, the nox, the sulphur, it almost doubles," Mr Cuffe said.
"We're talking about a really significant part of Ireland's emissions, and Europe's emissions are coming from aviation, and we simply cannot have endless growth."
As well as greenhouse gas emissions, Mr Cuffe said noise pollution in areas near the airport needed to be considered.
"It's also about ensuring that the people of north Dublin can have a decent night's sleep... people are really worried, even with the new flight patterns, that there will be a significant increase in noise over their homes in the years ahead.
Mr Jacobs said there had been consultation with local residents in area about the proposed expansion plans.
"There's €400m alone for sustainability investments. There's big investments in noise insulation, more noise in mitigation measures," he added.
Ryanair CEO Eddie Wilson puts some of the blame at daa’s door and says the discussion around emissions and noise pollution should have happened prior to now.
"We don't have a cap here because of environmental reasons. We've got a cap here because of incompetence. During Covid, daa didn't put in the planning application. We built two runways. The time to talk about all this stuff was when we were putting in two runways. We now have two runways in and we've less traffic," Mr Wilson said.
In reference to reducing emissions, Mr Wilson said: "Ryanair is playing its part, aviation companies are playing its part. What you have is aviation supports economic development in a small island in the northwest Atlantic, and it needs low cost access. It's the economic miracle.
Others say that additional flights should be transferred from Dublin Airport to regional airports. Last year, almost 2 million people flew in and out of Shannon Airport, but it is underutilised and has room for a further 2.5 million passengers.
"The regions have capacity to shoulder some of the burden of the congestion that Dublin is experiencing," Dee Ryan, CEO of Limerick Chamber said.
However, Mr Jacobs says there are examples of airports that have been built, but that are not used to their full capacity.
"There's a myth out there that if you cap Dublin, those flights will move to the regions. That's simply not the case," he said.
"The airlines want to come to Dublin. That's why they want to do more flights here," Mr Kenny added.
