The operation of any scheduled air service is a commercial decision for airlines, in consultation with airports and other market actors, based on the commercial viability of the route in question and other operational factors. Regulation (EC) No. 1008/2008 provides the framework for the operation of air services within the European Union, it is also provides that air operators have the freedom to set their own fares and rates.
I understand that for the Winter 2025 season, Kerry Airport has scheduled air services to Dublin, Frankfurt, London, and Manchester, providing point-to-point connectivity, and the opportunity for onwards connectivity to destinations in Europe, the Middle East, transatlantic, and further afield again.