I was watching a Seattle to Paris flight track today and it looks like perhaps the route they were taking was going to make the flight about 2+ hours longer. The flight left close to on-time but has been showing an arrival 147 minutes late all day. The track that the flight took went across southern Canada and left the US over Massachusetts. That's where the tracking ends but it projects the flight coming into France via Spain, apparently well away from the worst of the ash cloud.
Since the normal route of this flight would be through northern Canada, Greenland and into France from the north, I'm guessing that maybe the long 10 hour flight to Europe from the US west coast may be an even longer 12+ hour flight for awhile. I leave the 29th on this flight. That's why I was watching it.