Volcanic ash disruption: Evidence for precautions
25 May 2011 Last updated at 10:23 BST
Flights are expected to resume across the UK after a day that saw thousands of passengers affected by an ash cloud from the erupting Icelandic volcano.
Services in and out of Scotland, Northern Ireland and northern England were hit as about 500 flights were cancelled across Europe.
International Airlines Group CEO Willie Walsh told the BBC that his company carried out a test flight through the 'red zone' of the ash cloud which had closed airspace but found no ash in the area.
But Transport Secretary Phillip Hammond said this did not undermine the precautions in place.