Eyjafjallajökull just won't quit: New ash clouds from the Icelandic volcano have drifted across Europe, prompting another round of airport closures and flight cancellations across the U.K. and continental Europe Sunday. The ash shut down four Scottish airports, and Ryanair canceled 178 flights. In addition, Italian airspace was closed on Sunday morning, and other several carriers saw diversions and delays to and from Switzerland, southern and central France, and northern Portugal. Sunday’s problems cap off a week of ash-induced travel mayhem—and if winds carry the ash westward, the nightmare could continue. Airlines have lost $1 billion since April 14, having canceled 100,000 flights in the largest shutdown of European airspace since WWII.