Ireland's regional airports are in the wrong places, and a number of them are potentially not viable.
That is according to Edgar Morgenroth, Professor of Economics at DCU, who was speaking as the National Aviation Policy is up for discussion at the Oireachtas Transport Committee on Wednesday.
Professor Morgenroth told Newstalk Breakfast the country’s airports are all competing with each other, except Dublin.
"What we have is possibly airports in slightly the wrong places," he said.
"You've got Dublin on the east coast and you actually have all the regional airports on the west or south.
"To a degree, they're all competing with each other - except for Dublin, who dominates a very large space.
"Consequently, their scale is sort of limited.
"Dublin has dominated so much that there isn't any scope anymore - but if you started with a blank sheet, you might spread them around a little bit differently."
Kerry 'much more viable'
Prof Morgenroth gave his view of the regional choices.
"Donegal [Airport] is, in my view, in the wrong part of Donegal and it has very, very few services.
"It's utterly dependent on subsidised flights... you don't really have much of an airport.
"Kerry, because it has had proper commercial services going in there at some frequency, is much more viable.
"Waterford would be one that is probably less so.
"Galway is gone, and for good reasons – [it was] sandwiched between Knock and Shannon; one of these would definitely have to go".
'Strategic problem' in Dublin
Founder of Aer Lingus Regional Padraig Ó Ceide told the show it really comes down to numbers.
"Dublin has over 90% of all the passengers coming in and going out of Ireland," he said.
"We do have a particular, strategic problem in relation to Dublin Airport.
"It's the only airport in Europe, of any European capital cities that I'm aware of, that there's no train service directly to the airport.
"So, it creates huge traffic, huge environmental issues if we don't have a proper public transport system to and from the airport."
'We need an airport in Cork'
Mr Ó Ceide said the regional airports do serve a purpose.
"Cork is the second-largest city in Ireland; they in 2019 carried about 2.4 million passengers or thereabouts," he said.
"There is, in my view, a need for an airport in Cork.
"We've got the conovation [sic] around there, you've got the industry, you've got the tourism.
"The thing I'd say about Cork is, I actually think that there would be a need and a demand for a transatlantic flight out of Cork."
On Donegal, he believes the airport is in the wrong place when it comes to population, but not in other terms.
"I think the purpose of Donegal Airport is very different to just a huge population," he said.
"It takes about five hours to go from Gweedore to Dublin; I think Donegal is, in effect, an island on the island of Ireland.
"Then, if you look at Kerry... I think Kerry is fit for purpose.
"You do have some international flights... you do have a PSO to Dublin from Kerry.
"Kerry Airport is between Tralee and Killarney, which is the two major towns there".
'Partitionist' attitude
Prof Morgenroth said the argument for Donegal doesn't stack up.
"It's quite wrong to say, 'It's five hours to Dublin,'” he said. “It's a lot faster to two other international airports in Belfast."
"There tends to be a very partitionist view of this that completely ignores what's available in Northern Ireland.
"For Donegal, Dublin is not the closest big city: Belfast is," he added.
Listen back to the full segment below: