I booked Carnival airfare, so I am using the Carnival shuttle that came with it.
The Carnival shuttle is probably the easiest and most reliable option.
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Booked Cruises:
Carnival Dream for Thanksgiving
Eastern Caribbean- 11/20/2010
Past Cruises:
Carnival Ecstasy (4 Day Baja Mexico) 2003
Carnival Pride (7 Day Mexican Riviera) 2007
Carnival Spirit (8 Day Exotic Mexican Riviera) 2007
Carnival Freedom (7 Day Western Caribbean) 2008
Carnival Elation (4 Day Baja Mexico) 2009
Carnival Spirit (7 Day Southbound Alaska) 2009
We just booked transfers from Anchorage to Whittier - with the train. You might want to check into that ------- but I'm not sure about the airport. Sorry!