Hummer of all Moths

It's a bird, it's a plane, no it's.... a hummer-moth? I have no idea what this creature is, but it flies like a hummingbird and looks like a moth. It is the only one I've seen in the hill country, but I suppose they could be fairly common and I wouldn't know any better. Of course, with many things, once you see one and take notice, all of a sudden the world seems to be full of them. Have you ever bought a car and then noticed all the other cars just like yours? Maybe I'll start seeing hummer-moths at the local gas station, bookstore, and sandwich shop now. I'll put this flying wonder on my list of things to research a little on a slow day. Real slow.