THEY used to come in Viking longships. Now the Nordic invasion has taken to the skies. After a day of frenzied speculation on Friday, Icelandair, led by swashbuckling chairman Hannes Smarason, confirmed the rumour that it had bought an 8.4% stake in easyJet. Smarason, one of a clutch of youthful Icelandic entrepreneurs who made fortunes during the Nineties, said the stake, worth almost £50m, was a long-term investment and that he might buy more.