Have NATS / The Met Office / Eurocontrol got it horribly wrong?
Simon Calder, travel editor of the UK newspaper the Independent, says the airline Ukraine International is planning to resume flights at 1000 BST as they believe "the skies are safe". They have reportedly carried out a test flight and are happy with the results.
KLM Royal Dutch Airlines says it has already carried out a test flight from Amsterdam to Dusseldorf and plans eight more throughout the day.
"I got a call from somebody, a very senior figure in the British travel industry - saying the only time aircraft have actually suffered is when they've basically flown right through a volcanic plume as the volcano was erupting."
Is there a growing suspicion that the risk may have been misunderstood?