First, post-volcanic ash days, is fight insurance a new necessity?
Second, when do I buy this insurance: before, during, or after I purchase my fight tickets online?
Hi, LM. There are companies that sell it before or after purchase - usually after purchase though, they will exclude you for pre-existing medical conditions, etc, etc - find the place that you want to use, and read their policies.
Re covering the volcano: There were articles on the BBC and NY Times (I think it was the NY Times) that said most insurance companies are now considering the volcano a pre-existing condition, and not covering for insurance purchased after the initial eruption. FYI. Google it.