EDIT: this is the net downward displacement of air sufficient to equal the A380 850,984lb max landing weight assuming a ballpark air density of ~0.075 lb/ft^3.

EDIT: this is the net downward displacement of air sufficient to equal the A380 850,984lb max landing weight assuming a ballpark air density of ~0.075 lb/ft^3. The aircraft displaces much more air via its engines, fuselage and secondary effects, but the above number seems most relevant to the Challenger 604 ~1,000 feet beneath the aircraft :).