Airport shuttles are a great way to get to the airport if you are nearby or staying in a hotel with a shuttle. They are usually cheap and reliable. However they are not available everywhere, and usually have very specific pick-up locations.
In my opinion, the best way is to just take a cab. You can get from Manhattan to LaGuardia (or JFK) and back by subway or bus (see the Related Link below), but as far as I know, there is no direct...
There is an RER (regional rail system) station at one end of Charles De Gaulle Airport. It's fast and, unless you have a lot of people in your group, less expensive than taking a taxi.
If you are looking for the best route, Google Maps maps it out well. Coming out of Love Field, turn right on Mockingbird. Pass under IH 35 (Stemmons Fwy) and turn right on Highway 183. Stay on 183...
The best way is to fly, as there are flights between Dublin and Cork. The other options are road and rail. You can get a train from Heuston Station, which you can get a bus to from the airport. You...