If Dave knows who this year's featured artist is, he's holding the cards close to his chest. Not even a hint in his promo just before 10@10 today.
I checked Pollstar, as in the past they've posted artists and dates before the station spilled the news, but nothing so far for May 21.
I also checked Jet's routings, and they haven't announced any dates in the US til June, when they commence opening shows for Oasis. So I wouldn't rule them out entirely, but they don't have anything booked at all in that time-frame, and I'd expect that they'd have at least a few dates booked around then.