You can get static dissipative wax and spray. Not sure how well they hold up to weather, though. The ESD wax holds up on the floor ok. I suppose for airplanes one has to think about corrosion when considering doping the materials. Maybe a couple of square feet of doped paint around the filler? If you wanted to be really paranoid, I guess you could touch the nozzle and the doped paint at the same time, before filling. The static dissipative material has to touch something that's grounded to dissipate the charge. Kind of like scuffing your feet across the carpet and then touching the doorknob with a piece of wood before grabbing it with your hand. When evaluating something that's supposed to be static dissipative, you can't just touch it with VOM (voltohm meter) probes. You have to have a reasonable amount of area, and maybe even a little pressure. As I recall, we had a special instrument with flat metal probes that we'd press onto a surface to check it. I suppose if you put a large enough piece of metal on the surface of the material, you could check it with a VOM. I once made a safety cover with Plexiglas that was supposed to be static dissipative, but it turned out that only the outer surfaces were. I had to run a bunch of bolts with washers through to electrically connect the inside and outside. With the dissipative material, point contact didn't seem to be enough. I think red plastic gas tanks are supposed to be dissipative, but I don't know if that goes right through or if it's just the surfaces. If the latter, I don't know what measures there are to connect the inside and the outside. Maybe that's getting too paranoid. From a web search, it appears that there's a vast literature about static charges, sparks, and fuel. But I didn't run across any practical distillation, other than not getting back into your vehicle while refueling, and putting your gas can on the ground before filling.