Why rapid airlift does not replace logistics

Can air transport substitute for the logistics needed to reinforce a difficult theatre such as Afghanistan?

Air mobility is valuable but scarce and expensive for heavy forces; sustained operations need secure infrastructure and large-scale surface transport as well.

Aircraft can reinforce a secure base quickly, but a contested landing area and the mass of vehicles, ammunition, spares, and fuel change the calculation. A C-17 may carry a Challenger 2, yet the vehicle still needs ammunition, spares, maintainers, and a continuing supply flow after it lands. Strategic transports are scarce assets with many competing demands, so theoretical lift capacity is not the same as an affordable sustainment system. Rail infrastructure could have lowered the cost of moving heavy goods while giving Afghans a visible economic benefit.