Fill them with several tonne tungsten rods going the length of the fuselage and just dive at mach (which even a 737 can do — once).
Rods from G-d.
I’d probably put some sort of liquidizing thermite in for fun.
You could make the mother of all fuel air explosives. It probably wouldn’t crack a fortified installation but could be heard for a hundred miles and make a nice mushroom cloud.
Not as effective as filling it with JDAMs and dropping a cloud of GPS accurate bombs over a city.