We have had several of these gathering nectar from our lantana here in Eastern NC.  They almost look like little humming birds, with their wings beating rapidly.  They have black feathery antennae, they are black & yellow striped, but are flatter & bigger than bumblebees.  What are they?

Hi Lucy,

these sound like hawk moths to me. I'm not sure what species are local to you (being based in Britain and not much of a Lepidopterist), but they will probably be in the genus Hemaris. If you take a look for this name on google images you'll be able to see if this is correct. For a more accurate identification we really need a photo or a very detailed description.

I hope this helps!

In Europe, we have the hummingbird hawk moth _Macroglossum stellatarum_, which is a fairly regular visitor to Britain, you will have similar in the US, as Paolo says above.