I am staying one day in Iceland, can you recommend a local transportation that would be available from the International Airport in Reykjavik to the city?
There is so called Flybus. They sell the tickets for it on the plane. It takes 45 minutes to get from the airport in Keflavik to Reykjavik. Taxi is very expensive.
Do they accept credit cards on the plane or do you need to have Iceland's currency?
They accept credit card because most people don't have Iceland Krona before they land.
The Flybus is timed with each incoming and outgoing flight - that's how small that airport is. Very easy to get tickets and it's the cheapest and most efficient option http://www.re.is/Flybus/
Yvonne, I spent 4 days in Iceland in June and Never used currency. I used my debit and my credit for everything. Enjoy Iceland, it's incredible!