airports also provide important regional connectivity for business, tourism and weekly commuters
Agreed.
and in some instances need to absorb the additional costs to provide the services needed
Airports are labour intensive operations.
Opening late/early involves extra costs.
The vital question is;
is volume of traffic during the day sufficient to cover the extra costs in these services?
Are the local councils/Irish Government/Failte Ireland going to cover the potential shortfall?
Its far better to have a viable operation running core hours maximizing the utilization of its resources.
regional bus services would be significantly curtailed
Since 2010 Bus Eireann has been "restructuring" some of its rural routes.
While concentrating on the profitable routes between the main urban centres.