Camping Fan - 20000mAh Battery Powered Fan Rechargeable with LED Lantern - Portable Outdoor Tent Fans with Hanging Hook 4 Speeds Wind Remote Control, Black and Orange

Any battery powered fan like this rechargeable one works well - https://www.amazon.com/dp/B0D3DJHDSZ?ref=ppx_pop_mob_ap_share. This specific oscillates and should run for 8+ hrs on a medium speed. If you're sleeping in the car with this running, I could see a suction mount being another option (not sure if this fan supports easy mounting but it has a hook on the bottom at least, so perhaps it could be hung from the trunk latch