Is it easier to fly into Shannon if we're planning on seeing Dingle then Dublin?
It's about 3 hrs by car from Shannon to Dingle versus about 5 hrs from Dublin, so flying into Shannon and home from Dublin would be a good strategy. One-way car rental charges are typically not too bad in Ireland.
I would recommend Shannon.
In 2010, I decided to walk the 100-mile-long Dingle Way trail. I wanted to fly into Shannon, but there were no flights from Chicago the day I had left, so I had no choice but to fly into Dublin and then take a 30-minute flight back to the west. I wasted about four hours sitting in the Dublin airport and taking another flight. I would have liked to have relaxed before my week-long hike.
There are other options if your proposed itinerary would permit:
If you'll be getting off your flight in the morning after a long overnight flight, many here recommend hopping on the express bus direct from Dublin airport to Galway, spending at least a night there to get a good night's sleep, then collecting your car there for explorations of the pretty Connemara region or to begin a leisurely drive down the west coast towards Dingle.
Unless you're able to sleep on the redeye flight over and are comfortable that you'll be fit to drive immediately upon arrival, the consensus here is to wait a day before tackling unfamiliar roads in left-hand traffic. That's pretty good advice in my opinion.
Starting in Galway would give you at least a day to shed some of your jet lag before getting behind the wheel. You could then drop the car back in Dublin before your time there. Flying into and out of Dublin will probably be the cheaper option as well.
There's also the option of spending your time in Dublin at the beginning of your trip, which would give you a few nights to acclimate before beginning your driving adventure.
If Dingle is your primary focus you might look at one of the daily flights on RyanAir from Dublin to the Kerry airport near Killarney - about an hour's drive from Dingle. There are rental car outlets at the airport there, and there's the option of returning your car there once you've finished up your time in SW Ireland and catching a return flight back to Dublin for a last night in an airport hotel before your flight home.
Hello from Wisconsin,
An advantage to landing in Shannon is several fold. You are on the west coast. The airport is surrounded by farmland. So you get a clam place to start the lefthand driving. I always recommend getting several hours sleep, if not over night, before you start touring. I tried to find a place close by, very close by like Gort, Quinn, or Six-Mile-Bridge.
Then again, Ennis is a short bus ride away from the airport. A great old hotel to stay in. Meals and a high street to walk. And then pick up your car the next day either in Ennis or back at the airport. One fewer day of car rental fees. You also might consider a bus from the west coast to Dublin to catch your flight out. Once again, one fewer day of car rental.