The recovery at the Republic’s airports continued in 2023, with 39.2 million passengers using the six open for commercial traffic.

But the figure was only 3% ahead of the pre-COVID-19 total of 38.1 million in 2019, and the pandemic has exacted a high toll – traffic would be five or six million higher had previous growth trends continued.

Two regional airports have closed in recent years, Galway and Sligo, while there have been no scheduled services at Waterford since 2016.

Dublin Airport attracts 85% of all traffic in the Republic and 72% of all traffic on the island – 7.2 million use the three airports in Northern Ireland in addition to the 39 million who choose the Republic’s airports.

Figures for all nine operational airports, north and south, can be seen in Table 1.

Economics

The economics of airports are straightforward – new ones are costly, this is a fixed-cost business, and it makes little sense to build unless decent utilisation is likely. Revenue for a new facility needs to cover operating as well as capital costs.

In Ireland there were 12 airports north and south with scheduled service at the peak in the 1990s compared to just five airports 20 years earlier.

Until the 1970s, there were just three in the Republic at Dublin, Cork and Shannon, with just the two Belfast airports in Northern Ireland. The seven new airports were built or refurbished with State funds, and cater for just 3% of all-island traffic between them.

There was no need to open these airports in order to expand overall capacity, since the pre-existing facilities had capacity enough and three of the seven have ceased operations.

Only a few of the surviving nine are able to cover operating costs.

Dublin is a big international airport, and Belfast’s Aldergrove is busy enough to cover the costs. But a rule of thumb in airport economics is that airports below four or five million passengers per annum can struggle.

Some may be fortunate with low operating costs and can survive with as few as two or three million.

Some countries subsidise regional airports for understandable reasons – the Scottish and Greek islands or the remote Arctic provinces of Scandinavia are examples – since the natural passenger hinterland of an airport is two or three hours by surface transport.

Infrastructure

Better roads in recent decades and regular bus services to their larger competitors have undermined the traffic prospects of small Irish airports.

Carrickfin on the western coast of Donegal is an extreme example – the average daily volume is a little over 100 customers, dominated by travellers on the subsidised daily service to Dublin.

The closures of Galway, Sligo and Waterford followed the withdrawal of airlines unable to compete with better surface connections to Dublin as the national motorway network was being upgraded.

Cork does better than Shannon since Cork is bigger than Limerick, but is also further from the biggest competitor.

Traffic at Shannon is not much more than half the figures achieved during the pre-crash period and many passengers have opted for the M7. Shannon loses money on operations, concealed in the aggregate accounts of the Shannon Group.

Cork also loses money despite healthier traffic numbers – the losses are hidden in the accounts of the Dublin Airport Authority, which owns Cork Airport.

Northern Ireland

In Northern Ireland the local authority provides an annual subvention to cover losses at Derry Airport, notwithstanding improvements to the A6 route to Aldergrove, which have cut the surface connecting time to a little over an hour.

In these circumstances it is surprising that there are plans to reopen Waterford, with Government money expected for a runway extension.

More surprising is the private plan for a new two-runway airport at Arklow, just 70 minutes from Dublin along the M11 and M50.

The balance sheet value of Dublin is around €2.5 billion and the promoters of the Arklow airport have declined to furnish cost estimates.

There is a plan for yet another airport in Offaly, on a site close to the M4 motorway and just over an hour from Dublin Airport by road. Despite low traffic numbers, there are even plans for rail connections to both Cork and Shannon airports.