HDRs do not float and they must be airdropped at low altitudes, which you can't generally do over a city center.
You might want to tell the US Air Force that.
The HDRs were dropped from the air-planes via one-time-use,heavy-duty card-board containers called Tri-Wall Air De-livery Systems (TRIADs).
Each TRIAD contains 470–490 HDRs. As the planesapproach the drop zone, they are depressurized and the cargo doors are opened,then the pilots pull the aircraft nose upabout seven degrees,causing the contain-ers to roll out of the aircraft.
The containers are tied to a static line, or harness, that tightens and flips them over once they are clear of the aircraft,releasing the prepack-aged rations, which “float” down.
The empty cardboard container is then released, and the harness retracted. Thismethod eliminates the need to drop pallets of food via parachute, permits wide distribution of the rations, and prevents palletized loads from falling into enemy hands.