My son, friend, and I just went on a three night trip, we took this grill and just packed some charcoal in a freezer bag and then in one of our dry bags. It worked great, we grilled a pork tenderloin one night and kabobs the next. Perfect for three adult men, we probably could have grilled for 4 if we had tried.
It folded flat and slid nicely under my seat.
https://www.amazon.com/UCO-Flatpack-Portable-Stainless-Steel/dp/B06XWYQPMQ