A plane flies past a smoke plume resulting from the eruption of the Grimsvotn volcano, under the Vatnajokull glacier in southeast Iceland, May 21, 2011. Airlines began canceling flights to Britain because of the ash cloud from the volcano reaching its airspace, although experts expected no repeat of travel chaos from the eruption of Eyjafjallajokull a year ago. (Olafur Sigurjonsson/Reuters)