Normally I think carbon-fiber and titanium is often seen for tech fanbois who just want to show off, but...for this I think those would be very helpful to shave every possible ounce.
"hot-swapping" battery packs is something I don't think will ever catch on for personal car EV's, but for this, I'm certain it should be designed so the battery is swapped-out every time it lands, automatically. An auto-landing feature could easily have it land in a fairly precise spot, and facing a specific direction.