A street in Cahirceveen: One of Ireland's many.
Aer Lingus is the airline that has regular flights between major U.S. airports and Shannon and Dublin airports. It, Aer Arann Express and British Airways provide flights inside the Republic and between it and Northern Ireland. British Airways, Aer Lingus and other companies run flights between Ireland and the United Kingdom.
Cheaper flights are generally found in advance of the flight and in round-trip tickets. Flights are about six and a half hours from New York and 10 hours from Los Angeles.
Once in Ireland, travel by bus, rental car and bicycle is available. The republic's Bus Eireann makes long-distance trips and has local service in areas, including Cork, Galway, Limerick and Waterford. This is probably not the most feasible way to conduct daily travel in the off-season because some routes do not run at all, or only run daily or weekly.
Car rental agencies exist in many places though it is advised that the rental be made before you get to Ireland to make it cheaper.
The Car Rental Council of Ireland provides a list of rental companies that it approves. The Bord Failte's Web site states that most cars for rent are manual and not automatic.