Vapor Trail

Today's blip shows a phenomenon which I haven't seen in the sky since almost a week.
A vapor trail.

Since the vulcan Eyjafjallajökull in Iceland (really a tongue twister) threw a lot of ashes into the sky, almost all airports in Europe were or are still closed.
Some of my friends are stuck in London and in the US and I am curious if and when they make it back to Germany. This vapor trail gives at least some hope.