We were trying to get to London from Madrid in my plane to attend Google Zeitgeist. As I insisted in going there, and as the airports reopened, my pilots alerted me to the fact that the trick airlines are using to avoid the ash cloud is to fly long distances at very low altitudes.
This is something that I haven’t heard in the media. Flying long distances, at say 3000 feet, may be good to avoid the ash cloud, but it’s terrible for the environment. Aircraft consume twice the fuel to fly the same distance, and in general it is less safe. While most people think that low and slow may mean safety, the opposite is true in aviation where high and fast somehow works better.
We did not go in the end. We did not think it was safe to fly long distances at low altitude. And we did not know what effect that would have on the range of our small Citation Jet.