I’m seeing an either/or in most dictionaries I’ve checked with regard to duffel and duffle when used to refer to coats and bags. It seems to come from a Belgian town spelled Duffel.
What’s your take? I’d like to be definitive.
Interesting. According to Wikipedia both spellings are correct
A duffel bag (or duffle bag, kit bag, gym bag) is a large cylindrical bag made of cloth (or other fabric) with a drawstring closure at the top.
On the other hand Google NGram shows, that first spelling is more common in the last couple of decades. So just to be safe I’d use the duffel bag spelling.
P.S. Funny thing is that there are both Duffel Bags and Duffle Bag company and both are producing… that same bags 🙂