Those still believing that VA contamination is just theoretical construct could find the following link useful:
Met Office - Icelandic volcano - observations. Near the bottom of the page you can see where and when the test airplanes flew and what they found.
DLR's Falcon made second test flight yesterday, pollution has significantly dropped but there are still doubts whether the area is completely safe. For the time being,
report is available in German only.
MetAir has been flying its Dimona over Switzerland, I can't find link to their test results, though.