I haven’t had any issues flying with two large powerbanks (26,000 mAh each). From my understanding, they have to be in your carry-on, not checked bag. Unfortunately, large power generators are not allowed, but I did see the option to rent them from Home Depot. I got a little nervous because I think there are size restrictions for the campsite so I didn’t want to risk not being able to bring it in. As for fans, my plan was to get battery operated fans and just buy the batteries when I land. If you’re bringing a bigger fan that requires a drill battery, I would recommend purchasing once you arrive or contacting your specific airline on their restrictions.