I could have sworn that I've seen HM wearing this had fairly recently, but my jaunts through the Mad Hattery archives (like a crazy hat fashion show! I highly recommend it) produced nothing. It's not the hat that made me think of the White Witch in Scotland last December, and it's not the hat that more recently had me puzzled about whether it was yellow or cream.
So I'll send it out to my readers: is this a brand-spanking new hat busted out just for the visit to RAF Cranwell, or is it a repeat, as I suspected? Let me know in the comments on this post -- let's get this mad hattering chatter rolling!
Either way, I like it -- although the white/textured fabric combo does feel a tad wintery for May.
(ETA: Alison from The Royal Forums blog points out that the hat is a Rachel Trevor Morgan creation. Here's a link to her blog entry on the hat designer. Thanks, Alison!)