Don't know if they still require it, but in 2000, Icelandair required us to reconfirm a few days before the flight. Unfortunately for us, I didn't see the notice to do this. On the day of our flight I called to request seat assignments and was told that our reservation had been canceled because we failed to reconfirm. The customer service rep then said that the flight was sold out. However, we were able to fly standby and fortunately they had exactly 2 no-shows, so we made the flight. It was a very nervewracking wait to find out though. Since then, I ALWAYS call to reconfirm, even if it is not required. The peace of mind is worth the call to me.