yeah but theyve bin purposly flying in it, the argument airlines have is they only spend a very little time in it as they climb above it and therefore damage will be next to nonehttp://www.flightglobal.com/articles/2010/04/16/340727/pictures-finnish-f-18-engine-check-reveals-effects-of-volcanic.html
Images taken of the inside of an F-18 Hornet engine after flying through the cloud