In-air chemical refueling?
Not knowing which chems are used but remembering that someone may have said they are liquid, surely it wouldn't be beyond design capabilities to implement an aerial refueling rig with more than one hose, that also topped up the Jumbo's tanks whilst pumping in a fresh load (easy there, Mrs B, that was completely unintentional)? In theory, with aerial top-ups the Jumbo could stay on station and keep shooting for days if required.